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Volvo Md6a Md7a Workshop Manual


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            Workshop Manual           A
                       Engine unit   2 (0)

                              MD6A, MD7A

AB Volvo Penta
Customer Support
Dept. 42200
SE-405 08 Gothenburg
                 Workshop Manual

                 Marine diesel engines
                      MD6A, MD7A


Safety Precautions                        2

General information                       5

Repair methods                            6

MD6A                                      8
MD7A                                      9

Repair instructions                      10

Electrical system                        30

Special Tools                            34

Technical Data                           35

Safety Precautions
                                                              Check that the warning information decals on
This workshop manual contains technical data,                 the product are always clearly visible.
descriptions and repair instructions for Volvo Penta          Replace decals that have been damaged or
products or product versions contained in the contents        painted over.
list. Ensure that the correct workshop literature is being
used.                                                         Engine with turbocharger: Never start the en-
Read the safety information and the Workshop                  gine without installing the air cleaner (ACL).
Manual "General Information" and "Repair                      The rotating compressor in the Turbo can
Instructions" carefully before starting work.                 cause serious personal injury. Foreign
                                                              objects entering the intake ducts can also
                                                              cause mechanical damage.
In this book and on the engine you will find the
                                                              Never use start spray or similar to start the
following special warning symbols.
                                                              engine. The starter element may cause an
                                                              explosion in the inlet manifold. Danger of
         WARNING! If these instructions are not
                                                              personal injury.
         followed there is a danger of personal injury,
         extensive damage to the product or serious
                                                              Avoid opening the filler cap for engine
         mechanical malfunction.
                                                              coolant system (freshwater cooled engines)
                                                              when the engine is still hot. Steam or hot
         IMPORTANT! Used to draw your attention to
                                                              coolant can spray out. Open the coolant filler
         something that can cause damage, product
                                                              cap carefully and slowly to release pressure
         malfunction or damage to property.
                                                              before removing the cap completely. Take
                                                              great care if a cock, plug or engine coolant
NOTE! Used to draw your attention to important
                                                              line must be removed from a hot engine. It is
information that will facilitate work or operations.
                                                              difficult to anticipate in which direction steam
                                                              or hot coolant can spray out.
Below is a summary of the risks and safety precautions
you should always observe or carry out when operating
                                                              Hot oil can cause burns. Avoid skin contact
or servicing the engine.
                                                              with hot oil. Ensure that the lubrication
                                                              system is not under pressure before
         Immobilize the engine by turning off the power
                                                              commencing work on it. Never start or
         supply to the engine at the main switch(es) and
                                                              operate the engine with the oil filler cap
         lock it (them) in the OFF position before
                                                              removed, otherwise oil could be ejected.
         starting work. Set up a warning notice at the
         engine control point or helm.
                                                              Stop the engine and close the sea cock
                                                              before carrying out operations on the engine
         Generally, all servicing should be carried out
                                                              cooling system.
         with the engine switched off. Some work
         (carrying out certain adjustments for example)
                                                              Only start the engine in a well-ventilated
         requires the engine to be running. Approaching
                                                              area. If operating the engine in an enclosed
         a running engine is dangerous. Loose clothing
                                                              space, ensure that exhaust gases and
         or long hair can fasten in rotating parts and
                                                              crankcase ventilation emissions are
         cause serious personal injury.
                                                              ventilated out of the working area.
         If working in proximity to a running engine,
         careless movements or a dropped tool can
         result in personal injury. Avoid burns. Take
         precautions to avoid hot surfaces (exhausts,
         turbochargers, charge air pipes and starter
         elements, etc.) and liquids in supply lines and
         hoses when the engine is running or has been
         turned off immediately prior to starting work on
         it. Reinstall all protective parts removed during
         service operations before starting the engine.

Always use protective goggles where there is a      Store oil and fuel-soaked rags and fuel and
danger of pieces of metal, sparks from              oil filters safely. In certain conditions oil-
grinding, acid or other chemicals being thrown      soaked rags can spontaneously ignite. Used
into your eyes. Your eyes are very sensitive,       fuel and oil filters are environmentally
injury can lead to loss of sight!                   dangerous waste and must be deposited at
                                                    an approved site for destruction together with
Avoid skin contact with oil. Long-term or           used lubricating oil, contaminated fuel, paint
repeated contact with oil can remove the            remnants, solvent, degreasing agents and
natural oils from your skin. The result can be      waste from washing parts.
irritation, dry skin, eczema and other skin
problems. Used oil is more dangerous to health      Never allow a naked flame or electric sparks
than new oil. Use protective gloves and avoid       near the batteries. Never smoke in proximity
using oil-soaked clothes and rags. Wash             to the batteries. The batteries give off
regularly, especially before meals. Use the         hydrogen gas during charging which when
correct barrier cream to prevent dry skin and to    mixed with air can form an explosive gas -
make cleaning your skin easier.                     oxyhydrogen. This gas is easily ignited and
                                                    highly volatile. Incorrect connection of the
Most chemicals used in products (engine and         battery can cause a spark which is sufficient
transmission oils, glycol, petrol and diesel oil)   to cause an explosion with resulting damage.
and workshop chemicals (solvents and paints)        Do not disturb battery connections when
are hazardous to health Read the instructions       starting the engine (spark risk) and do not
on the product packaging carefully! Always fol-     lean over batteries.
low safety instructions (using breathing appara-
tus, protective goggles and gloves for exam-        Never mix up the positive and negative
ple). Ensure that other personnel are not           battery terminals when installing. Incorrect
unwittingly exposed to hazardous substances         installation can result in serious damage to
(by breathing them in for example). Ensure that     electrical equipment. Refer to wiring
ventilation is good. Handle used and excess         diagrams.
chemicals according to instructions.
                                                    Always use protective goggles when
Be extremely careful when tracing leaks in the      charging and handling batteries. The battery
fuel system and testing fuel injection nozzles.     electrolyte contains extremely corrosive
Use protective goggles! The jet ejected from a      sulfuric acid. If this comes into contact with
fuel injection nozzle is under very high pres-      the skin, wash immediately with soap and
sure, it can penetrate body tissue and cause        plenty of water. If battery acid comes into
serious injury There is a danger of blood           contact with the eyes, immediately flush with
poisoning.                                          copious amounts of water and obtain
                                                    medical assistance.
All fuels and many chemicals are inflammable.
Ensure that a naked flame or sparks cannot ig-      Turn off the engine and turn off power at
nite fuel or chemicals. Combined with air in cer-   main switch(es) before carrying out work on
tain ratios, petrol, some solvents and hydrogen     the electrical system.
from batteries are easily inflammable and
explosive. Smoking is prohibited! Ensure that       Clutch adjustments must be carried out with
ventilation is good and that the necessary          the engine turned off.
safety precautions have been taken before
carrying out welding or grinding work. Always
have a fire extinguisher to hand in the

Use the lifting eyes mounted on the engine/re-        When working on-board ensure that there is
verse gear when lifting the drive unit.               sufficient space to remove components
Always check that lifting equipment is in good        without danger of injury or damage.
condition and has sufficient load capacity to lift
the engine (engine weight including reverse           Components in the electrical system, ignition
gear and any extra equipment installed).              system (gasoline engines) and fuel system
To ensure safe handling and to avoid                  on Volvo Penta products are designed and
damaging engine components on top of the              constructed to minimize the risk of fire and
engine, use a lifting beam to raise the engine.       explosion. The engine must not be run in
All chains and cables should run parallel to          areas where there are explosive materials.
each other and as perpendicular as possible in
relation to the top of the engine.                    Always use fuels recommended by Volvo
If extra equipment is installed on the engine al-     Penta. Refer to the Instruction Book. The use
tering its center of gravity, a special lifting de-   of lower quality fuels can damage the
vice is required to achieve the correct balance       engine. On a diesel engine poor quality fuel
for safe handling.                                    can cause the control rod to seize and the
Never carry out work on an engine suspended           engine to over-rev with the resulting risk of
on a hoist.                                           damage to the engine and personal injury.
                                                      Poor fuel quality can also lead to higher
Never remove heavy components alone, even             maintenance costs.
where secure lifting equipment such as
secured blocks are being used. Even where
lifting equipment is being used it is best to carry
out the work with two people; one to operate
the lifting equipment and the other to ensure
that components are not trapped and damaged
when being lifted.

General information
About the workshop manual                                      Certified engines
This workshop manual contains technical specifica-             The manufacturer guarantees that certified new and
tion, descriptions and instructions for repairing the          currently operational engines meet national and re-
standard versions of the following engines                     gional environmental regulations (in Lake Constance
TAMD31M, TAMD31L, TAMD31P, AD31L, AD31P,                       for example). The product must be the same as the
KAD32P, TAMD41H, TAMD41M, TAMD41P, AD41P,                      example approved for certification purposes. So that
TAMD42WJ, KAMD42A, KAMD42B, KAMD42P,                           Volvo Penta, as a manufacturer, can guarantee that
KAD42A, KAD42B, KAD42P, KAMD43P, KAD43P,                       currently operational engines meet environmental
KAMD44P, KAD44P. The workshop manual displays                  regulations, the following service and replacement
the operations carried out on any of the engines               part requirements must be observed:
above. As a result the illustrations and pictures in the
manual that show certain parts on the engines, do              · The Service Intervals and maintenance operations
not in some cases apply to all the engines listed                recommended by Volvo Penta must be observed.
above. However the repair and service operations
described are the same in all essential details.               · Only Volvo Penta genuine replacement parts, in-
Where they are not the same this is stated in the                tended for the certificated engine, may be used.
manual and where the difference is considerable the
operations are described separately. Engine                    · The servicing of ignition, timing and fuel injection
designations and numbers are given on the number                 systems (gasoline) or injector pumps, pump set-
plate (See Workshop manual Group 21 Engine page                  tings and injectors (diesel) must always be carried
15). The engine designation and number should be                 out be an authorized Volvo Penta workshop.
given in all correspondence about the engine.
                                                               · The engine must not be modified in any way apart
This Workshop Manual has been developed primarily                from with accessories and service kits developed
for Volvo Penta service workshops and qualified per-             for it by Volvo Penta.
sonnel. Persons using this book are assumed to
have a grounding in marine drive systems and be                · No modifications to the exhaust pipes and air
able to carry out related mechanical and electrical              supply ducts for the engine room (ventilation
work.                                                            ducts) may be undertaken as this may effect ex-
                                                                 haust emissions.
Volvo Penta is continuously developing their prod-
ucts. We therefore reserve the right to make chang-            · Seals may only be broken by authorized person-
es. All the information contained in this book is based          nel.
on product data available at the time of going to print.
Any essential changes or modifications introduced                IMPORTANT! Use only Volvo Penta Genuine
into production or updated or revised service                    Parts.
methods introduced after the date of publication will            Use of non-original AB Volvo Penta spare
be provided in the form of Service Bulletins.                    parts will result in AB Volvo Penta being un-
                                                                 able to assume liability for the engine meet-
                                                                 ing engine certification requirements.
                                                                 Any type of damage resulting from the use of
Replacement parts                                                non-original Volvo Penta replacement parts for
                                                                 the product will not be covered under any war-
Replacement parts for electrical and fuel systems are            ranty provided by AB Volvo Penta.
subject to statutory requirements (US Coast Guard
Safety Regulations for example). Volvo Penta Genu-
ine parts meet these requirements. Any type of dam-
age which results from the use of non-original Volvo
Penta replacement parts for the product will not be
covered under any warranty provided by Volvo

Repair methods
The working methods described in the Service                   Our joint responsibility
Manual apply to work carried out in a workshop. The
engine has been removed from the boat and is                   Each engine consists of many connected systems
installed in an engine fixture. Unless otherwise stated        and components. If a component deviates from its
reconditioning work which can be carried out with the          technical specification the environmental impact of
engine in place follows the same working method.               an otherwise good engine may be increased
                                                               significantly. It is therefore vital that wear tolerances
Warning symbols occurring in the Workshop Manual               are maintained, that systems that can be adjusted
(for their meaning see Safety in formation)                    are adjusted properly and that Volvo Penta Genuine
       WARNING!                                                Parts as used. The engine Maintenance Schedule
                                                               must be followed.

        IMPORTANT!                                             Some systems, such as the components in the fuel
                                                               system, require special expertise and special testing
NOTE!                                                          equipment for service and maintenance. Some com-
are not in any way comprehensive since it is impossi-          ponents are sealed at the factory for environmental
ble to predict every circumstance under which                  reasons. No work should be carried out on sealed
service work or repairs may be carried out. For this           components except by authorized personnel.
reason we can only highlight the risks that can arise
when work is carried out incorrectly in a well-                Bear in mind that most chemicals used on boats are
equipped workshop using working methods and tools              harmful to the environment if used incorrectly. Volvo
developed by us.                                               Penta recommends the use of biodegradable de-
                                                               greasing agents for cleaning engine components, un-
All procedures for which there are Volvo Penta spe-            less otherwise stated in a workshop manual. Take
cial tools in this Workshop Manual are carried out us-         special care when working on-board, that oil and
ing these. Special tools are developed to rationalize          waste is taken for destruction and is not accidentally
working methods and make procedures as safe as                 pumped into the environment with bilge water.
possible. It is therefore the responsibility of any per-
son using tools or working methods other than the              Tightening torques
ones recommended by us to ensure that there is no              Tightening torques for vital joints that must be tight-
danger of injury, damage or malfunction resulting              ened with a torque wrench are listed in workshop
from these.                                                    manual `Technical Data": "Tightening Torques" and
                                                               are contained in work descriptions in this Manual. All
In some cases there may be special safety precau-              torques apply for cleaned threads, screw heads and
tions and instructions for the use of tools and chemi-         mating surfaces. Torques apply for lightly oiled or dry
cals contained in this Workshop Manual. These spe-             threads. If lubricants, locking fluid or sealing com-
cial instructions should always be followed if there           pound are required for a screwed joint this
are no separate instructions in the Workshop                   information will be contained in the work description
Manual.                                                        and in "Tightening Torques' Where no tightening
                                                               torque is stated for a joint use the general tightening
Certain elementary precautions and common sense                torques according to the tables below. The tightening
can prevent most risks arising. A clean workplace              torques stated are a guide and the joint does not
and engine eliminates much of the danger of injury             have to be tightened using a torque wrench.
and malfunction.
                                                               Dimension                   Tightening Torques
It is of the greatest importance that no dirt or foreign                                  Nm              lbt.ft
particles get into the fuel system, lubrication system,        M5                          6               4,4
intake system, turbocharger, bearings and seals                M6                          10              7,4
when they are being worked on. The result can be               M8                          25              18,4
malfunction or a shorter operational life.                     M10                         50              36,9
                                                               M12                         80              59,0
                                                               M14                        140             103,3

Tightening torques-protractor (angle)                          To ensure service work is correctly carried out it is
tightening                                                     important that the correct sealant and locking fluid
                                                               type is used on the joint where the agents are re-
                      Tightening using both a torque           quired.
                      setting and a protractor angle
                      requires that first the                  In this Volvo Penta Service Manual the user will find
                      recommended torque is applied            that each section where these agents are applied in
                      using a torque wrench and then           production states which type was used on the
                      the recommended angle is                 engine.
                      added according to the
                      protractor scale. Example: a             During service operations use the same agent or an
                      9Q0 protractor tightening                alternative from a different manufacturer.
                      means that the joint is
                      tightened a further 1/4 turn in          Make sure that mating surfaces are dry and free from
                      one operation after the stated           oil, grease, paint and anti-corrosion agent before ap-
                      tightening torque has been               plying sealant or locking fluid.
                                                               Always follow the manufacturer's instructions for use
                                                               regarding; temperature range, curing time and any
                                                               other instructions for the product.
                                                               Two different basic types of agent are used on the
Do not re-use lock nuts that have been removed dur-            engine and these are:
ing dismantling as they have reduced service life
when re-used - use new nuts when assembling or re-             RTV agent (Room temperature vulcanizing). Use for
installing. For lock nuts with a plastic insert such as        gaskets, sealing gasket joints or coating gaskets.
Nylock® the tightening torque stated in the table is           RTV agent is clearly visible when a component has
reduced if the Nylock® nut has the same head height            been dismantled; old RTV must be removed before
as a standard hexagonal nut without plastic insert.            the joint is resealed.
Reduce the tightening torque by 25% for bolt size 8
mm or larger. Where Nylock® nuts are higher, or of             The following RTV agents are mentioned in the Serv-
the same height as a standard hexagonal nut, the               ice Manual: Loctite® 574, Volvo Penta 840879-1,
tightening torques given in the table apply.                   Permatex®

                                                               No. 3, Volvo Penta P/N 1161099-5, Permatex® No.
                                                               77. Old sealant can be removed using methylated
Tolerance classes                                              spirits in all cases.
Screws and nuts are divided into different strength            Anaerobic agents. These agents cure in an absence
classes, the class is indicated by the number on the           of air. They are used when two solid parts, for exam-
bolt head. A high number indicates stronger material,          ple cast components, are installed face-to-face with-
for example a bolt marked 10-9 indicates a higher              out a gasket. They are also commonly used to se-
tolerance than one marked 8-8. It is therefore                 cure plugs, threads in stud bolts, cocks, oil pressure
important that bolts removed during the disassembly            switches and so on. The cured material is glass-like
of a bolted joint must be reinstalled in their original        and it is therefore colored to make it visible. Cured
position when assembling the joint, It a bolt must be          anaerobic agents are extremely resistant to solvents
replaced check in the replacement parts catalogue to           and the old agent cannot be removed. When
make sure the correct bolt is used.                            reinstalling the part is carefully degreased and then
                                                               new sealant is applied.

Sealants                                                       The following anaerobic agents are mentioned in the
                                                               Service Manual: Loctite® 572 (white), Loctite® 241
A number of sealants and locking liquids are used on           (blue).
the engines. The agents have varying properties and
are used for different types of jointing strengths, oper       NOTE! Loctite® is the registered trademark of Loctite Corporation,
ating temperature ranges, resistance to oil and other          Permatex® is the registered trademark of the Permatex
chemicals and for the different materials and gap siz-
es in the engines.


1.    Recess for starting crank
2.    Oil filling, engine
3.    Sealed crankcase ventilation
4.    Intake silencer
5.    Connection, fuel inlet
6.    Feed pump
7.    Reduction reverse gear MS, red.
8.    Control lever, reverse gear
9.    Oil filling, reverse gear
10.   Oil pressure contact
11.   Lubricating oil filter
12.   Start-generator
13.   Fuel filter
14.   Water-cooled exhaust manifold
15.   Decompression handle
16.   Injectors
17.   Temperature sender
18.   Cooling water outlet
19.   Thermostat housing
20.   Throttle lever
21.   Stop lever
22.   Fuel injection pump
23.   Oil dipstick, engine
24.   Fuel return line connection
25.   Sea-water pump
26.   Oil dipstick, reverse gear

1.    Oil dip-stick and oil filling, reverse gear
2.    Cover, cooling water pump
3.    Bleed-screw, fine filter
4.    Fine filter
5.    Decompression handle
6.    Pressure pipe nut
7.    Temperature sender
8.    Injector
9.    Thermostat housing
10.   Oil filling, engine
11.   Hand start
12.   Cooling water drain, engine
13.   Fuel injection pump
14.   Oil dip-stick, engine
15.   Cooling water drain, reverse gear
16.   Air cleaner and intake silencer
17.   Sender, rev, counter
18.   Fuel pump (with hand pump)
19.   Cooling water inlet, reduction gear
20.   Oil drain, reverse gear, reduction gear
21.   Warner, low oil pressure
22.   Oil filter

Repair instructions
Drain the cooling water and oil from the engine. Then        3. Remove the thermostat housing (2 bolts) and the
clean the outside of the engine. Remove the reverse             hose clamp under the housing. Take the
gear, 4 bolts.                                                  thermostat out of the exhaust manifold. Note the
                                                                small O-ring which seals against the exhaust
Removal                                                         manifold.

1. Remove the air cleaner, disconnect the
   alternator electric cables and the oil pressure
   cable, remove the alternator and the drive belts.
   Then remove the sea-water pump, the oil filter,
   the fuel filter and the feed pump. (Look out for
   fuel and oil splash.)

2. Remove the injectors and pipes as well as the
   leak-off oil pipe. Discard the sealing washers on
   both sides of the leak-off oil pipe.                      4. Remove the exhaust manifold (4 bolts).

5. Remove the rocker arm cover (2 nuts), the intake        7. a. (BOSCH pump) Disconnect the pipe from the
   manifold (4 bolts), the rocker arm (2 nuts) and            fuel filter and remove the nuts for the fuel
   the cylinder head (9 bolts). Take care of the              injection pump.

                                                           7. b. (CAV pump) Disconnect the pipe from the fuel
                                                              filter and remove the nuts for the fuel injection

6. Remove the cover on which the water pump is
   mounted. NOTE! Two of the five bolts are
   shorter than the other three and are placed
   towards the centre of the engine. Take care of
   the control bracket. Discard the old gasket.

                                                           8. Remove the nut which drives the water pump.
                                                              Use the flywheel as a counterhold. Remove the
                                                              fuel injection pump and the gear wheel.

9. Remove the timing gear cover. NOTE! The small             11. Knock out the hand starter pin in the camshaft.
   round cover on which the fuel pump is mounted                 Remove the protective cover (2 bolts). NOTE!
   has bolts with 3 different lengths. The bolts for             Scrap the sealing ring and fit a new one.
   the large casing has two lengths. The two bottom
   bolts are shorter than the others. Carefully lever
   loose the timing gear casing from its guide pins.
   Discard the gasket.

10. Remove the flywheel. Remove the nut and use a            12. Remove the front cover behind the flywheel (11
    puller. The axle is tapered and provided with a              bolts). Note the guide pins. Carefully tap all
    key. Use a counterhold when releasing the nut.               round. Replace the gasket and the sealing ring.

13. Remove the sump as well as the nut and lock             15. Remove the bolt for the intermediate gear. Dis-
    washer for the camshaft. Use a counterhold on               card the sealing washer 1 under the bolt. Pull off
    the crankshaft.                                             the intermediate gear.

14. Bend down the lock washer and release the bolt          16. Check that the shaft pin 1 for the intermediate
    securing the reverse gear flange to the                     gear is secure.
    crankshaft. Use a counterhold. NOTE! Take care
    of the key. Lever loose the rubber damper with a

17. Remove the gearwheel for the camshaft by tap-                 19. Invert the engine and remove the oil strainer (2
    ping the camshaft on the flywheel side with a                     bolts and 1 nut).
    plastic mallet or similar tool. Lift out the shaft and
    take care of the cover.

                                                                  20. Unscrew the bolts and remove the caps. Then
                                                                      carefully tap out the pistons and connecting rods.
                                                                      Place connection rods and caps in the same pai-
                                                                      ring as when removed to prevent them getting
                                                                      mixed up if they are not marked. NOTE! Also
                                                                      mark the piston and connecting rod for the re-
                                                                      spective cylinders (see point 21). On earlier engi-
                                                                      nes there is no marking on the pistons and con-
18. Remove the 4 bolts holding the timing gear ca-                    necting rods. During overhauling, these engines
    sing. The casing also sits on guides. Carefully le-               must be marked in the same way as those
    ver all round and remove the casing.                              produced later on.

21. Mark the connecting rod and cap nearest the fly-           23. Remove the centre nut and washer for the gear
    wheel with a peener. Peen as shown in Fig. 21.                 wheel on the lubricating oil pump. The shaft is ta-
                                                                   pered and the gear wheel sits on a key.

22. Remove the main bearing caps and lubricating
    oil pump.
    The main bearing caps are marked with a 2 or 3.
    The corresponding figures are punched into the             24. Remove the bolts (4) from the pump body cover
    block. Replace the axial bearings 1. Check that                and lift off the cover. Clean the body and check
    the guide 2 for the caps is in good condition. Lift            that the gears are in good condition. Replace da-
    out the crankshaft.                                            maged parts.

25. Re-fit the gears as shown in the Fig. below. Fit             27. Check for wear on pistons, piston rings and gud-
    the cover together with a new gasket. Tighten up                 geon pins. Replace if necessary. The piston and
    the 4 bolts and rotate the shaft to make sure that               connecting rod must be matchfitted as shown in
    it does not jam. Fit the key in its groove and re-fit            fig. A. Make absolutely certain that the groove
    the gear wheel. Fit the spring washer and tighten                ring for the gudgeon pin is fitted in its groove.
    up the gear with the nut.                                        The piston rings are fitted with a piston ring rod.
                                                                     Begin with the oil ring 1 (fig B) in the lowest
                                                                     groove. Continue with the compression ring 2.
                                                                     Finally fit the compression ring 3. NOTE! The
                                                                     marking TOP must face upwards. The other two
                                                                     rings can be faced as desired.

26. Remove the bolt 1 for the relief valve and check
    that the spring 2 and piston are in good
    condition. If there is anything suspicious about
    the opening pressure of the relief valve, check
    the data for the spring. See under "Technical                Crankshaft
    Data, Lubricating oil pump".                                 28. Check the drive gear on the crankshaft for wear
    Clean and re-fit the piston and spring and tighten               or damage. Remove the drive gear with a puller.
    up the bolt.                                                     Remove the key and clean the shaft. Check for
                                                                     wear and grind the shaft if necessary. (See
                                                                     under "Technical Data".) Clean the engine block
                                                                     and all other parts which must be re-fitted.

Cylinder head                                                  31. Replacing the valve guides.
                                                                   With excessive clearance between the valve
29. Remove the valve tappets. NOTE! Carefully                      stem and valve guide, the valve guide must be
    machine clean the valve tappets where they                     replaced. (See under "Technical Data".) Press
    have been smoothed down (1) in order to serve                  out the valve guides with tool 884538.
    as a counterhold for the torque wrench. Do not
    force out the valve tappets as this could damage
    the block etc.

30. Remove the seals on the valve stems. Remove
    the valve springs with the help of a valve spring
    remover. Remove all the collets 1. Remove the
    valves. IMPORTANT! Place the valves in the or-
    der in which they are removed. Discard burnt
    valves if the wear is excessive and grind valve
    seats if necessary (See under Technical Data).
    Seats and valves must be ground together so
    that the contact surfaces will be absolutely tight.

                                                               32. Fit new valve guides with tool 884549. Use a

Removing the nozzle sleeves                                   Installing the valves

33. Insert the expander screw on tool 884541 into             35. Thoroughly clean the cylinder head, valve guides
    the copper sleeve and screw anti-clockwise until              and valve seats. Use a small brush. Check that
    the screw has expanded and fastened in the                    the bevel on the seats is correctly ground by
    sleeve. Then pull hard so that the threads go into            applying marking blue to the bevel on the valve
    the copper material. Fit the yoke on the stud                 disc and rotating it against the seat under light
    bolts holding the injector. Screw on the nut and              pressure. If the blue is not distributed evenly on
    rotate until the sleeve is removed.                           the entire bevel surface of the seat (this indicates
                                                                  a leaky valve), grind the valve further and re-
                                                                  check until results are successful. The width of
                                                                  the seat should be approx. 1 mm (0.04").
                                                                  Oil the valve stems before filling them in their re-
                                                                  spective guides. IMPORTANT! Make sure that
                                                                  the valves and valve springs are re-filled in their
                                                                  original positions. Place the cylinder head on its
                                                                  edge and fit the valve springs and collets 2. Use
                                                                  a valve spring tool. Finally fit the rubber seal 1
                                                                  (MD6A) on the intake valves.

34. Replacing the 0-ring which seals between sleeve
    and cylinder head.
    Dip the 0-ring in soapy water before fitting it.
    Wash and blow clean before filling the new
    injector sleeve with tool 884539. knock in the
    sleeve until it bottoms. Check to make sure that
    the 0-ring is not damaged or has moved.

                                                              Checking the cylinder head level finish

                                                              36. If there is any doubt as to the level finish of the
                                                                  cylinder head after carrying out repairs, check as
                                                                  Completely disassemble the cylinder head and
                                                                  clean it thoroughly. Measure with the help of a
                                                                  steel ruler (check the ruler against a flat disc) by
                                                                  placing it on the cylinder head face as shown by
                                                                  the arrows in the diagram below. Then measure
                                                                  with a feeler gauge the gap between the ruler
                                                                  and the face of the cylinder head at the marked
                                                                  measuring points. A maximum gap of 0.00--0.10
34. a. Oil the spreader tool                                      mm (0.00--0.004") measured crisscross (see
    884537 and push the                                           diagram below) and 0.00--0.10 mm (0.00--
    tool into the sleeve (en-                                     0.004") measured laterally (see diagram below)
    sure that the bolt is                                         is approved. If the measured gap is between
    screwed back suffi-                                           0.10 mm (0.004") and 0.20 mm (0.008"), then the
    ciently). Place nuts or                                       gap must be grinded. If the gap exceeds 0.20
    washers on the stud                                           mm (0.008"), replace the cylinder head with a
    bolts so that the yoke                                        new one.
    can be securely attach-
    ed with nuts. Screw the
    tool down as far as the
    recess in the injector
    sleeve allows. Thus
    pressing out the sleeve.
    Remove the tool.

Pressure-testing the injectors                                 Overhauling the feed pump

37. Check the spray pattern at an opening pressure             39. Exert force on the pump lever (see Fig.). If the
                  2           2
    of 180 kp/cm (2560 Ibf/in ). Also check that the               pump "squeaks" then it is in good condition. If it
    fuel jets cease simultaneously at all four holes               does not, the diaphragm must be replaced. This
    and there is no dripping afterwards.                           is done as follows:

Adjusting the opening pressure

38. Adjust the opening pressure with adjuster
    washers 1, which are available in different                40. Release the cover centre screw, lift out the strai-
    thicknesses ranging from 1 mm (0.04") to 1.95                  ner 1 and clean it.
    mm (0.08") at intervals of 0.05 mm (0.002")
    between each washer.
    Screw apart the injector and replace the adjuster
    washer with a thinner or thicker one depending
    on whether the pressure has to be reduced or in-
    creased. Screw the injector together again and
    check the opening pressure and spray pattern.
    Continue this procedure until results are satisfac-

41. Unscrew the six bolts holding the upper and             43. Undo the screw 1, and pull out the manual pump
    lower sections of the pump body together.                   lever 2 and replace the spring 3 if in poor condi-
    Remove the pump lever spring 1, and unscrew                 tion. NOTE! keep an eye on the rubber seal
    the screw 2, which holds the pump lever shaft.              which is pressed into the body.

                                                            44. Thoroughly clean the pump body and replace
                                                                worn parts.
                                                                Re-fit the manual pump lever. Press the di-
                                                                aphragm in and fit the pump lever onto the di-
                                                                aphragm shaft. Then insert the shaft and tighten
                                                                it with the screw. IMPORTANT! Do not forget the
                                                                washer on the screw.
                                                                Place the strainer on the upper body section and
                                                                screw tight the cover and gasket. Assemble the
                                                                pump body halves and fit the retaining washer 1
                                                                for the spring 2 on the mechanical pump lever 3.
42. Press down the diaphragm and shake forwards                 IMPORTANT! The retaining washer can only be
    the pump lever shaft 1 until the pump lever loo-            filled in one way. Fit the spring and then the 0-
    sens. Then pull the diaphragm out of the body.              ring 4 which seals against the engine.

Overhauling the sea-water pump                                  47. Remove the sealing rings 2 and the 0-ring 1
                                                                    (earlier engines), and clean the pump body and
45. Remove the cover (6 bolts). Replace the impeller                shaft. (IMPORTANT! The pump must be
    with the help of two screwdrivers or similar tools.             removed from the engine.) Check to make sure
    IMPORTANT! Protect the edges on the pump                        there is no burr on the shaft. NOTE! A new 0-ring
    body. See Fig. below. Lever out the impeller with               must not be fitted.
    the screwdrivers so far that the bolt becomes vi-

                                                                48. Fit new sealing rings. IMPORTANT! Turn the
                                                                    sealing rings so that they are in their proper
                                                                    position and make sure that they do not block
                                                                    the drain hole in the pump body Grease the shaft
46. Unscrew the bolt and pull the impeller off the                  and carefully fit it into the body. Screw it through
    shaft. If the sealing rings also have to be repla-              the sealing rings but make sure the rings are not
    ced, the shaft can be pulled out entirely together              damaged when doing so. Place the shaft so far
    with the impeller, after which the bolt can be rele-            into the housing that the bolt hole is outside: Fit
    ased.                                                           the impeller and screw in the bolt. Then carefully
                                                                    push in the impeller until it bottoms. Place a new
                                                                    gasket on the cover and tighten up with the 6

Checking the thermostat                                       51. Oil and fit the bearing halves in the caps. Place
                                                                  the caps according to the marking on the block.
49. Lower the thermostat into hot water and with a                Fit the remaining axial bearing halves on the
    thermometer test to see whether the thermostat                intermediate cap with the oil grooves facing
    opens and closes at the right temperature. It                 outwards. NOTE! Fit a new 0-ring on the rear
                               0       0
    should start opening at 60 C (140 F) and be fully             cap which is integrally built with the lubricating oil
    open at 74CC (165 F). If the thermostat is faulty,            pump. The tightening torque for the main
    it must be replaced. Clean and fit a new rubber               bearings is 50 Nm (5 kpm = 36 Ibftf). Turn the
    gasket 1 on the thermostat. Place a new 0-ring 2              engine.
    for the water hole on the lower edge of the
    thermostat housing and fit the housing on the
    exhaust manifold.

                                                              52. Turn the piston rings so that their respective
                                                                  gaps are apart from each other. The piston top is
INSTALLING THE ENGINE                                             marked with "Front" and should point towards the
                                                                  flywheel. NOTE! Fit the connecting rod which is
50. Before installing, heat the crankshaft drive gear.            marked with punch pops nearest the flywheel.
    Place the key in the key slot on the crankshaft               Carefully tap the piston downwards through the
    and press on the new drive gear.                              installation tool with a wooden handle or similar.
    Fit new bearing shells. Oil the bearings. Install             Place the engine on its side and tighten up the
    the crankshaft. Fit an axial bearing half 1 on                caps. Tightening torque = 50 Nm (5 kpm = 36
    each side of the intermediate main bearing with               Ibftf). Lock the bolts with the lock washers.
    the oil grooves 2 facing outwards.

53. Fit the "protective cover" for the starting crank.        55. Fit a new gasket and install the timing gear
    Replace the sealing ring and gasket.                          casing (4 bolts). Tap carefully so as not to
                                                                  deform the guide pins.

54. Fit the camshaft. Observe due care so that the            56. Fit the key in the camshaft and then the gear
    sealing ring in the protective cover for the                  wheel. Turn the gear wheel so that the figure
    starting crank is not damaged. Knock the                      which is punched on the ring gear faces
    starting crank pin into the camshaft. Use a tube              outwards. Fit the star washer and the nut on the
    or similar as a counterhold.                                  camshaft. Tighten up later on (see Point 59).
                                                                  When a new engine block is used, a new shaft
                                                                  pin 1 for the intermediate gear must be fitted.

57. Fit the intermediate gear. Check that the                59. Install the fuel injection pump. Use a new
    punched-in figures on the crankshaft drive and               gasket. Fit the key on the pump shaft and install
    camshaft gear wheel coincide with the marking                the gear wheel. IMPORTANT! The figure must
    on the intermediate gear.                                    face towards the figure on the intermediate gear.
                                                                 Tighten up the gear wheel with the nut which
                                                                 also functions as a flange for the water pump.
                                                                 Tightening torque = 60 Nm (6 kpm = 43 Ibftf).
                                                                 Use a counterhold.
                                                                 Tighten the camshaft nut. Remove the counter-

                                                             60. Fit the cylinder head gasket. It can only be fitted
58. Place the large flat washer on the intermediate              in one way. If the stud bolts in the cylinder head
    gear with the bevel facing outwards, and                     must be replaced, fit the new ones to a torque of
    thereafter the steel-rubber washer 1. Tighten                20 Nm (2 kpm = 14 Ibffi). Fit the cylinder head.
    with the bolt. NOTE! On earlier engines a plastic            All the nuts must have washers under them
    washer is used. This must be scrapped and                    except the one on which the lift eyelet is filled.
    replaced by the steel-rubber one.                            Tightening torque = 70 Nm (7 kpm = 50 Ibm).

                                                                 NOTE! Tightening is in three stages.

                                                                    First stage: 10 Nm (1 kpm = 7 Ibm)
                                                                    Second stage: 40 Nm (4 kpm = 29 Ibffi)
                                                                    Third stage: 70 Nm (7 kpm = 50 Ibm).

                                                                    See tightening scheme below.

61. Place a new gasket on the inner timing gear               63. Place a new gasket on the water pump and fit it
    cover and fit the outer timing gear casing. Two               with the two bolts. Make sure that the groove in
    short bolts are fitted at the bottom. Trim off any            the pump shaft engages in the flange nut.
    part of the gasket which sticks out.

62. Fit a new gasket and cover where the water                64. Fit the cover with new gasket over the camshaft
    pump is to be installed. NOTE! The control                    end. NOTE! The bolts have three different
    bracket is fitted with one of the bolts. Two bolts            lengths. The Fig. below shows where they are
    are shorter.                                                  placed.

65. Install the fuel pump. Make sure that the 0-ring            67. Fit the oil sump together with a new gasket. The
    is in position. Use a new 0-ring. The pump is                   gasket can only be fitted in one way. Begin with
    installed with two inhex bolts and spring                       the four corner bolts for locating the sump into
    washers. Check that the pump "squeaks" by                       position. Tighten all the bolts thoroughly.
    pressing in the pump lever before installing the                Remove the sealing ring on the casing for the
    pump on the engine. Connect up the fuel hoses.                  crankshaft (flywheel side). Fit a new sealing
                                                                    ring. Trim off any part of the oil sump gasket that
                                                                    is sticking out. Place a new gasket on the cover
                                                                    and fit it. Carefully knock on the cover until it fits
                                                                    over the guide pins. Tighten up the cover with
                                                                    the bolts.

66. Release the lock wire securing the lubricating oil          68. Fit the rocker arm, fuel filter and fuel lines.
    strainer. Lift out the strainer, wash it and blow it            NOTE! Replace the fine filter insert (see page
    dry with compressed air. Re-fit it and lock it with             25, Point B) by turning the hex head in the
    the lock wire. Turn the engine and fit the                      bottom of the container. When the installation of
    complete oil strainer.                                          the engine is completed, bleed the fuel system
                                                                    through the bleeder screw 1. See more detailed
                                                                    instructions about this on page 25, Point B.

69. Fit the key for the flywheel and push on the fly-               71. MD6A. Install the stars generator with its
    wheel. Fit the thick washer and tighten up the                      bracket. Screw tight the tensioning bar to the
    flywheel with the nut. Tightening torque = 180                      engine. Earlier engines have a washer placed
    Nm (18 kpm = 130 lbftf). Use a counterhold                          between the engine and bracket.
    through the flywheel.                                               MD7A. Install the alternator with its bracket.
                                                                        Screw tight the tensioning bar to the engine.

70. Oil the oil filter rubber gasket. Fit the oil filter and        72. Install the exhaust manifold. Fit a new gasket.
    the oil pressure contact. Screw in the oil filter so                Check to make sure that the rubber hose for the
    far that the rubber gasket just touches the                         cooling water is in good condition. Fit the cooling
    engine. Then screw tight a further half turn.                       water hose from the cooling water pump and
    IMPORTANT! Screw by hand.                                           tighten up the hose clamp.

73. Fit the injectors and the overflow pipe.                 75a. Adjusting the CAV fuel injection pump
    Tightening torque for injectors' nuts 1 = 8 Nm           a. Rotate the flywheel in a clockwise direction until
    (0,8 kpm = 5,8 lbftf). NOTE! Do not forget the               both the valves on No. 1 cylinder are closed
    new sealing washers 2 on both sides of the                   (compression stroke).
    overflow pipe.                                           b. Assemble the pump so that the marking coinci-
                                                                 des with that on the transmission housing see
                                                             c. Fit on the gear wheel. NOTE! The figure (1) is to
                                                                 be turned towards the figure (1) of the
                                                                 intermediate wheel.
                                                             d. Bleed the air from the pump with the bleed-
                                                                 screws in the following order 1, 2, 3.

74. Fit the fuel pipes between the injection pump
    and the injectors. NOTE! Check to make sure
    that the brake pipes are properly installed, see

                                                             76. Adjust the valves as follows:
                                                                 Rotate the flywheel until both valves on a
                                                                 cylinder "rock". Turn the flywheel one further
75. Adjusting the BOSCH injection pump                           turn and adjust the valves for this cylinder.
a. Turn over the engine until the valves in cylinder             Repeat the procedure for the other cylinder.
    No. 2 "rock'. Continue to turn over the engine in            With a hot engine, the clearance should be 0.30
    the normal direction of rotation until marking 10            mm (0.012") for both the intake and exhaust
    on flywheel coincides with the marking on the                valves.
b. Remove the pump inspection cover and check
    that the marking (1) coincides exactly with the
    pointer (2). Adjustments are made by slackening
    the pump securing nuts and turning the pump.
c. Tighten the nuts.
d. Check the setting by turning over the engine 1/4
    turn in the opposite direction of rotation, then
    back again to the "10,' marking on the flywheel.
    Check that the marking (1) and the pointer (2)
    still coincide.
e. Fit the inspection cover with the rubber gasket.

77. Oil the rocker arm and fit the rocker arm cover         79. Fit the key in the crankshaft. Heat the flange and
    together with new gaskets. Fit the intake                   fit it on the shaft. Tighten it up with the bolt and
    manifold and gasket and install the air cleaner.            the thick washer. Tightening torque: 80 Nm (8
    Fit the ventilation hose between the rocker arm             kpm = 57 lbftf). Bend down the thin washer over
    cover and air cleaner.                                      the bolt head. Fit the rubber damper.
    NOTE! Fit the intake manifold with the flange
    displaced towards the reverse gear side in order
    to provide space for the air cleaner.

                                                            80. Install the reverse gear and gasket and connect
78. Fit the V-belts and tension the alternator. The             up the cooling water hose between the reverse
    belts are properly tensioned when they can be               gear and water pump. Then fit the exhaust
    depressed under normal thumb pressure about                 elbow.
    3 - 4 mm (1/8"). Depress between the start-
    generator and flywheel.

                                                            81. Fill the engine and reverse gear with oil. Concer-
                                                                ning the oil quantity and quality, see under
                                                                "Technical Data".

Electrical system
                                                            3. When starting with the help of a helper battery,
82. The following applies to engines fitted with               first check that the helper battery has the same
    alternators:                                               rated current as the standard one. Connect the
1. Never break the current between the                         helper battery to the standard battery, positive to
    alternator and battery while the engine is                 positive and negative to negative. Remove the
    running. If a main switch is fitted, it must not           helper battery when the engine has started.
    be switched off until the engine has stopped.              Note! The cables to the standard battery must
    Otherwise no cable must be disconnected while              not be broken.
    the engine is running, since this also can ruin         4. With electrical welding on the engine or instal-
    the charging regulator.                                    lation components, the charging regulator cables
2. Check regularly the battery, battery cables and             must first be disconnected and insulated. Both
    cable terminals. The battery poles should be               the battery cables must also be disconnected.
    well-cleaned and the cable terminals always             5. In the event of repairs to the alternator
    well-tightened and well-greased to ensure                  equipment, both battery cables must first be
    continuous function. All cables in general must            disconnected. The same applies if the battery
    be well-tightened, there must be no loose                  has to be rapidly charged.
    connections. Note! On no account must the               6. Never test any of the components with a
    battery's positive and negative poles be mixed             screwdriver, etc. against a terminal to see if it
    up when the battery is fitted.                             sparks.

Fig. 82 Wiring diagram for the MD6A with start-generator (no rev counter and temp. gauge)

Cable Marking                                  1. Starter button
 Des.     Colour       mm           AWT       2. Key switch
  A"      Beige        2.5           13       3. Charging warning light
 B Bl     Black        1.5           15       4. Control light for oil pressure
  C        Red          25            3       5. Switch
  C        Red         2.5           13       6. Terminal board, instrument panel resp. engines
  D       Green        1.5           15       7. Charging regulator
  D       Green        2.5           13       8. Start-generator
  G       Brown        1.5           15       9. Oil pressure indicator
  H        Blue        1.5           15       10. Battery 12V, max. 60 Ah
  H        Blue         25            3       11. Main Switch

Fig. 83. Wiring diagram for late prod. Type MD6A

1. Key switch
2. Instrument panel switch
3. Temperature gauge
4. Warning light for "low oil pressure"
5. Rev counter
6. Warning light, charging start-generator
7. Switch, optional equipment
8. Terminal board
9. Warning light, charging alternator
   (Optional Equipment)
10. Battery
11. Main switch
12. Start-generator
13. Alternator (Optional Equipment)
14. Charging regulator
15. Fuse
16. Temperature sender
17. Rev counter
18. Oil pressure sender
19. Other electrical equipment

Wiring Diagram MD7A
Des.    Colour              mm
A       White                 6              9
B       Black                1.5            15
B'      Black                0.6            19
B"      Black               0.75            18
C       Red                   6              9
C'      Red                  35              1
C"      Red                 0.6             19
F       Yellow               1.5            15
G       Brown                1.5            15
H       Blue                  4             11
H'      Blue                 35              1
I'      Green/red           0.75            18
J       Green                1.5            15
J'      Green               0.6             18
J"      Green               0.75            18
K       Blue/yellow         0.75            18
L       White/red           0.75            18
M       Blue/red            0.75            18

Position List
2. Charging warning light
3. Warning light for "high temperature"
4. Warning light for "low oil pressure"
5. Key switch                                    12. Alternator
6. Siren                                         13. Fuse
7. Alarm unit                                    14. Main switch
9. Place for instrument, extra equipment         15. Battery
10. Terminal board                               16. Temperature sender
11. Starter motor                                17. Oil pressure sender

FAULT TRACING                                                                                                                                      Bleeding the fuel system
                                                                                                                                                        To ensure that the engine starts, the fuel system must
The fault-tracing scheme below includes only those                                                                                                      be bled on the following occasions: 1) When changing
faults which arise most often during operation.                                                                                                         the fine filter. 2) When draining through the drain plug.
                                                                                                                                                        3) When cleaning the pre-filter. 4) When running the
Fault-tracing scheme                                                                                                                                    fuel tank empty. 5) When installing the fuel injection
                                                                    Engine runs unevenly or                                                             pump. 6) With leakage and when working on the fuel
                                         right operating speed at
                                         Engine does not reach
 Engine does not start

                                                                    vibrates abnormally                                                                 line. 7) When the engine has been stopped for a long
                                                                                                                                                        time. Bleeding is as follows: Open the bleeder screw 1
                                                                                              Engine becomes
                                                                                              abnormally hot         FAULT            Notes             on the fine filter. See Point 68. Pump forward the fuel
                          Engine stops

                                                                                                                                                        with the help of a hand primer until about 0.2 litre (0.2
                                         full throttle

                                                                                                                                                        qt.) fuel has run out. Close the bleeder screw. If you
                                                                                                                                                        get poor pumping effect, turn over the engine a bit so
                                                                                                                                                        that the pump drive cam alters its position. If the fuel
                                                                                                               Main switch not on,
                                                                                                                                                        injection pump has been removed, or when starting an
 X                                                                                                             flat battery, broken    A
                                                                                                                                                        entirely new engine for the first time, the fuel injection
                                                                                                               electric cables
                                                                                                                                                        pump must be bled. Pump with the hand primer for
                                                                                                               Empty fuel tank,
                                                                                                                                                        about 1/2 minute. This automatically bleeds the fuel
 X                        X                                                                                    closed fuel cock,       B
                                                                                                                                                        injection pump. Slacken the delivery pipe nuts for the
                                                                                                               blocked fuel filter
                                                                                                                                                        injectors and turn over the engine with the start-
                                                                                                               Water, air or                            generator until fuel comes from the delivery pipes.
 X                        X                                                X                                                           B
                                                                                                               impurities in fuel                       Tighten up the delivery pipe nuts and start the engine.
 X                        X                     X                          X                                   Defective injectors     C
                                                                                                               Boat abnormally                     C.   Check the injectors with regard to their opening
                                                X                                                              loaded. Growth on       D                pressure, tightness and spray pattern. Max. running
                                                                                                               boat bottom.                             time of 400 operating hours or once a season is
                                                X                          X                                   Damaged propeller       E                recommended between these checks. See also Points
                                                                                                               Clogging of cooling                      37 and 38.
                                                                                                               water intake,
                                                                                                  X            cooling jackets,         F          D.   In order to get the best possible operating economy,
                                                                                                               defective impeller                       the engine speed selected should be minimum 300
                                                                                                               or thermostat                            rev/mm below the max. speed for The engine during
                                                                                                                                                        lengthy periods of operation. When the boat has been
A. Check the state of charge of the battery with the help                                                                                               in the water for so' time, the max. speed for the engine
                         of a hydrometer which shows the specific gravity of the                                                                        can drop due to growth on the outside of the hull. Use
                         battery acid. This will vary with the state of charge, see                                                                     anti-fouling paint. Check and clean the hull regularly.
                         under "Technical Data". Also see under "Electrical
                         system" on page 23.                                                                                                       E.   Check the propeller blades. If a propeller blade is
                                                                                                                                                        damaged, the propeller must be replaced. A propeller
B. Replace the fine filter by turning the hex head in the                                                                                               blade can also be warped, something which is very
                         bottom of the container. The fine filter and container                                                                         difficult to discover. Place the propeller on a flat disc
                         are of the throw-away type. They must be discarded                                                                             and measure the blades. If a propeller blade is
                         and a new one installed. Check that the contact                                                                                warped, the propeller should be replaced.
                         surface for the cover is absolutely clean and that the
                         filter gasket is in good condition. Screw on the new                                                                      F.   Check the cooling system for leakage, clogging, etc.
                         filter tight by hand until the gasket goes against the
                                                                                                                                                        Check to make sure the thermostat opens at the right
                         cover. Then tighten the filter a further 1/2 turn. The
                                                                                                                                                        temperature. The thermostat can be removed after
                         bottom of the filter container has a drain plug for
                                                                                                                                                        having taken down the thermostat housing at the front
                         draining water and impurities that have accumulated in
                                                                                                                                                        of the exhaust manifold. See also Point 49. The pump
                         the fuel. Bleed the fuel system after draining and
                                                                                                                                                        body in the sea-water pump is made of neoprene
                         replacing the filter, also check for leakage.
                                                                                                                                                        rubber, which can be damaged with shortage of water,
                         Remove the feed pump cover and clean the pre-filter
                                                                                                                                                        e.g., in the event the sea-water inlet is blocked.
                         in the fuel oil. Then fit the filter with the pins facing
                         upwards and place the gasket (undamaged) in position                                                                           Proceed according to Points 45-48 in the event the
                         and tighten up the cover. Bleed the fuel system.                                                                               impeller and sealing rings have to be replaced. NOTE!
                         Check and if necessary drain the extra fuel filter if such                                                                     If the boat is in the water, the bottom cock must be
                         is fitted. Look out for fuel splash.                                                                                           closed before the sea-water pump is removed. But do
                                                                                                                                                        not forget to open the cock again.

Special Tools
Part No.   Description








Technical Data
Technical Data MD6A
Type designation                                               MD6A
Output (DIN) at 40 rev/sec (2400 rev/mm)                       7.4 kW (10 h.p.)
Number of cylinders                                            2
Bore                                                           70 mm (2.7560")
Stroke                                                         82 mm (3.2283")
Capacity                                                       0.63dm
Compression ratio                                              18.7:1
                                                                             2              2 1)
Compression pressure at starter motor speed                    23--25 kp/cm (327--355 lbf/in )
Direction of rotation, viewed towards flywheel                 Clockwise
Idling speed                                                   12 rev/sec (700 rev/min)
                                                                       2         2
Oil pressure, hot engine                                       4 kp/cm (57 lbf/in )
                                                                         2          2
Oil pressure, idling, hot engine                               0,8 kp/cm (11 lbf/in )

Material                                                       Cast iron
Bore, standard                                                 70.000--70.019 mm (2.7560--2.7566")
0.500 mm (0.020") oversize                                     70.500--70.519 mm (2.7755--2.7763")

Material                                                       Light-metal
Height, total                                                  81 mm (3.19")
Height from gudgeon pin centre to piston crown                 51 mm (2.00")
Piston clearance in cylinder                                   0.086--0.130 mm (0.0034--0.0051")
Pistons, standard                                              69.889--69.914 mm (2.7515--2.7525")
0.500 mm (0.020") oversize                                     70.389--70.414 mm (2.7712--2.7722)

Gudgeon pins
Diameter                                                       27.9975--28.0025 mm (1.1023--1.1025")
Gudgeon pin bushing, diameter                                  28.0125--28.0225 mm (1.1029--1.1032")
Clearance, gudgeon pin -- bushing                              0.010--0.025 mm (0.0004--0.0010")

Piston rings
Compression rings, number                                      2
Oil scraper ring, number                                       1
Upper compression ring has chromium lining
Piston rings are available for standard size and 0.500 mm
(0.020") oversize
Piston ring clearance in groove, axially:
Upper compression ring                                         0.062--0.113   mm (0.0024--0.0044")
Lower compression ring                                         0.037--0.087   mm (0.0015--0.0034")
Oil scraper ring                                               0.037--0.089   mm (0.0015--0.0035")
Piston ring gap in cylinder:
Upper compression ring                                         0.279--0.406   mm (0.0110--0.0160")
Lower compression ring                                         0.203--0.330   mm (0.0080--0.0130")
Oil scraper ring                                               0.350--0.480   mm (0.0140--0.0189")

Material                                                       Nodular iron
Crankshaft axial clearance                                     0.08--0.31 mm (0.0031--0.0122")
Main bearing radial clearance                                  0.026--0.075 mm (0.0010--0.0030")
Connecting rod radial clearance                                0.026--0.075 mm (0.0010--0.0030")
     Measured with Moto Meter nipple 884535 and yoke 884543.

Main bearing journals
Diameter, standard                            49.984--50.000 mm (1.9679--1.9685")
0.300 mm undersize                            49.684--49.700 mm (1.9560--1.9567")
0.600 mm undersize                            49.384--49.400 mm (1.9442--1.9449")

Main bearing shells
Thickness, standard                           1.730--1.737 mm (0.0681--0.0684")
0.300 mm oversize                             2.030--2.037 mm (0.0800--0.0802")
0.600 mm oversize                             2.330--2.337 mm (0.0917--0.0920")

Connecting rod journals
Diameter, standard                            49.984--50.000 mm (1.9679--1.9685")
0.300 mm undersize                            49.684--49.700 mm (1.9560--1.9567")
0.600 mm undersize                            49.384--49.400 mm (1.9442--1.9449")

Connecting rod shells
Thickness, standard                           1.730--1.737 mm (0.0681--0.0684")
0.300 mm oversize                             2.030--2.037 mm (0.0800--0.0802")
0.600 mm oversize                             2.330--2.337 mm (0.0917--0.0920")

Connecting rods
End play at crankshaft                        0.25--0.50 mm (0.0100--0.0200")

End play                                      0.160--0.300 mm (0.0063--0.0118")
Radial clearance in bearing                   0.017--0.083 mm (0.0007--0.0033")
Camshaft diameter                             43.992--44.008 mm (1.7320--1.7326")
Lift height of cams                           5.48--5.52 mm (0.2157--0.2173")
Bushing, diameter                             44.025--44.075 mm (1.7333--1.7352")

Cylinder head
Material                                      Special-alloy cast iron

Intake valves
Disc diameter                                 28.8--29.0 mm (1.1338--1.1417")
Stem diameter                                 7.938--7.960 mm (0.3125--0.3134")
Valve seat angle                              29.25--29.50°
Cylinder head seat angle                      30°
Width of seat in cylinder head                approx. 1 mm (0.040")
Clearance, hot engine                         0.30 mm (0.012")

Exhaust valves
Disc diameter                                 26.3--26.5 mm (1.0354--1.0433")
Stem diameter                                 7.938--7.960 mm (0.3125--0.3133")
Valve seat angle                              29.25--29.50°
Cylinder head seat angle                      30°
Width of seat in cylinder head                approx. 1 mm (0.040")
Clearance, hot engine                         0.30 mm (0.012")

Valve guides                                  43 mm (1.6930")
Length, intake valve                          49 mm (1 .9291")
Length, exhaust valve                         8.000--8.022 mm (0.3150--0.3158")
Bore                                          10.7--11.0 mm (0.4212--0.4331")
Height above cylinder head spring face        0.040--0.084 mm (0.0016--0.0033")
Clearance, valve stemguide

Valve springs
Length, off-load                                   47 mm (1 .8504")
Loaded with 150 N (15 kp = 33 Ibf.)                30 mm (1.1811")
Loaded with 230 N (23 kp = 50 lbf.)                21 mm (0.8268")

Lubricating system
Oil capacity excl. filter                          2.8 litres (2.5 Imp.qts. = 2.9 US qts.)
Oil capacity incl. filter                          3.0 litres (2.6 lmp.qts. = 3.2 US qts.)
Oil quality acc. to API-system                     CD (DS)
                        0    0
Viscosity, above +10 C (50 F)                      SAE 30
                        0   0
Viscosity, below +10 C (50 F)                      SAE 20W
                                                                     2                   2
Oil pressure, hot engine, idling speed             0.8--1 .5 kp/cm (11 .4--2 1 .3 Ibf/in )
                                                                    2              2
Oil pressure, hot engine, full speed               3.5--4.0 kp/cm (50--57 lbf/in )

Reverse gear
Oil quality/Viscosity                              Same as for engine
Oil capacity, din (qts.), red. 1:1                 0.4 (0.4)
Oil capacity, din (qts.), red. 1.91 :1             0.55(0.5)

Combi reduction gear
Reduction gear                                     same oil compartment as engine's
Reversing mechanism and propeller hub              Lubricating grease Shell Alvania EP2 or similar

Lubricating oil filter
Designation                                        AC-DELCO, 1530838 type SA

Lubricating oil pump
Type                                               Gear wheel pump
Relief valve spring: Length, off-load              45 mm (1.7717")
Loaded with 15 N (1.5 kp = 3.3 lbf)                40 mm (1.5748")
Loaded with 46 N (4.6 kp = 10 Ibf)                 29 mm (1.1417")
Axial clearance of gear wheels incl. gasket        0.048--0.084 mm (0.0020--0.0033")

Fuel system
Fuel injection pump, make Bosch                    0 460 302 006
Injectors, make Bosch, holders                     0 431 112 001
Nozzles                                            0 433 171 001
Hole diameter                                      Four, 0.22 mm (0.0087")
                                                             2           2
Opening pressure                                   180 kp/cm (2560 Ibf/in )
Spray angle                                        150°
Advance angle                                      12°
Injection quantity                                 20 mm /stroke at 31.7 rev/sec
                                                   (1900 rev/min)
Max. speed                                         40.8--42.5 rev/sec (2450--2550 rev/min)

Fine filter
Type                                               Bosch 0 450 133 001
Filter insert                                      Bosch 1 457 434 0611

Feed pump
Type                                               Pierburg PE 15672
                                                                   2                 2
Feed pressure at 40 rev/see (2400 rev/mm)          0.65--0.85 kp/cm (9.2--12.0 lbf/in )

Electrical system
Battery voltage                                               12 V
Battery capacity                                              Max. 60 Ah
Start-generator                                               Bosch 0 010 350 004
Generator output, max                                         135W
Generator output, continuous                                  90 W
Starter motor output                                          0.74kW (1 h.p.)
Battery electrolyte specific gravity: Fully charged batter    1.275--1.285 g/cm
When charging has to be carried out                           1.230 g/cm

Cooling system
Thermostat                                                    Bellows thermostat
                                                                0       0
Starts opening at                                             60 C (140 F)
                                                                0       0
Fully open at                                                 74 C (165 F)

Drilled with wear (or if engine has abnormal fuel
consumption)                                                  0.25 mm (0.010)

Main bearing and connecting rod journals
Permitted out-of-roundness                                    0.06 mm (0.0024")
Permitted taper                                               0.05 mm (0.0020")
Max. axial play on crankshaft                                 0.36 mm (0.0142")

Bearing journals, permitted out-of-roundness                  0.03 mm (0.0012")
Max. clearance between camshaft and bushings                  0.15 mm (0.0060")

Max. clearance between valve stem and guide                   0.16 mm (0.0063')
Edge of valve disc should be mm                               1.0 mm (0.0400")

                                                              Nm             Kpm    Lbftf
Cylinder head nuts                                            70             7      51
Cylinder head stud bolts                                      20             2      14
Bolt for flange on crankshaft                                 70             7      50
Flywheel nut                                                  180            18     130
Connecting rod bolts                                          50             5      36
Water pump flange                                             60             6      43
Main bearings                                                 50             5      36
Nuts for fork for injectors                                   8              0.8    5.8

Tightening scheme for cylinder head nuts

Technical Data MD7A
Type designation                                              MD7A
Output at flywheel (DIN) at 43 rev/sec. (2600 rev/mm.)        10 kW (13.4 h.p.)
Number of cylinders                                           2
Bore                                                          76 mm (2.9921")
Stroke                                                        82 mm (3.2283")
Capacity                                                      0.744 dm
Compression ratio                                             17:1
                                                                                       2                  2
Compression pressure at starter motor speed                   2-2.5 MPa (20--25 kp/cm ) (284--355 lbf/in )
Direction of rotation, viewed towards flywheel                Clockwise
Idling speed                                                  11--13 rev/sec (650--780 rev/min)
                                                                                          2               2
Oil pressure, full speed, hot engine                          0.35-0.40 MPa (3.5-4.0 kp/cm ) (50-57 lbf/in )
                                                                                          2               2
Oil pressure, idling, hot engine                              0.08-0.15 MPa (0.8-1.5 kp/cm ) (11-21 lbf/in )

Material                                                      Cast iron
Bore, standard                                                76.00--76.03 mm (2.9921--2.9933")
0.25 mm (0.010") oversize                                     76.25--76.28 mm (3.0020--3.0032")
0.50 mm (0.020") oversize                                     76.50--76.53 mm (3.0118--3.0130")

Material                                                      Light-alloy
Height, total                                                 76.4 mm (3.0079")
Height from gudgeon pin centre to piston crown                51.4 mm (2.0236")
Piston clearance in cylinder                                  0.073--0.118 mm (0.0029--0.0046")
Pistons, standard diameter                                    75.912--75.927 mm (2.9883--2.9893")
0.25 mm (0.010") oversize                                     76.162--76.177 mm (2.9985--2.9991")
0.50 mm (0.020") oversize                                     76.412--76.427 mm (3.0084--3.0090")

Gudgeon pins
Diameter                                                      28.000--28.004 mm (1.1024--1.1025")
Gudgeon pin bushing, diameter                                 28.0125--28.0225 mm (1.1029--1.1032")
Clearance, gudgeon pin - bushing                              0.0085--0.0230 mm (0.0003--0.0009")

Piston rings
Compression rings, number                                     2
Oil scraper ring, number                                      1
The upper compression ring is chromium lined
Piston rings are available for standard size, 0.250 mm
(0.010') and 0.500 mm (0.020") oversize

Piston ring clearance in groove, axially:
Upper compression ring                                        0.070--0.102 mm (0.0028--0.0040")
Lower compression ring                                        0.050--0.082 mm (0.0020--0.0030")
Oil scraper ring                                              0.030--0.062 mm (0.0012--0.0024")

Piston ring gap in cylinder
Upper compression ring                                        0.30--0.50 mm (0.0120-0.020")
Lower compression ring                                        0.30--0.50 mm (0.0120-0.020")
Oil scraper ring                                              0.25--0.50 mm (0.010-0.020")

Material                                                      Nodular iron
Crankshaft axial clearance                                    0.080--0.313 mm (0.0032--0.0123")
Main bearing radial clearance                                 0.026--0.075 mm (0.0010--0.0030")
Big-end bearings, radial clearance                            0.026--0.075 mm (0.0010--0.0030")

Main bearing journals
Diameter, standard                            49.984--50.000 mm (1 .9679--1.9685")
0.300 mm (0.0120") undersize                  49.684--49.700 mm (1.9560--1.9567")
0.600 mm (0.0236') undersize                  49.384--49.400 mm (1.9442--1.9449")

Main bearing shells
Thickness, standard                           1.730--1.737 mm (0.0681--0.0684)
0.300 mm (0.0120") oversize                   1.880--1 .887 mm (0.0740--0.0743")
0.600 mm (0.0236") oversize                   2.030--2.037 mm (0.0799--0.0802")

Big-end journals
Diameter, standard                            49.984-50.000 mm (1.9679--1.9685")
0.300 mm (0.0120") undersize                  49.684--49.700 mm (1.9560--1.9567")
0.600 mm (0.0236") undersize                  49.384--49.400 mm (1.9442--1.9449")

Big-end bearing
Thickness, standard                           1.730--1.737 mm (0.0681--0.0684")
0.300 mm (0.0120") oversize                   1.880--1.887 mm (0.0740--0.0743")
0.600 mm (0.0236") oversize                   2.030--2.037 mm (0.0799--0.0802")

Connecting rods
End play at crankshaft                        0.25--0.50 mm (0.0100--0.0200")

End play                                      0.160--0.300 mm (0.0063--0.0118")
Radial clearance in bearing                   0.01 8--0.083 mm (0.007--0.0033")
Camshaft diameter                             43.992--44.008 mm (1 .7320--1.7326")
Lift height of cams                           5.48--5.52 mm (0.2157--0.2173")
Bushing, diameter                             44.026--44.075 mm (1 .7333--1.7352")

Cylinder head
Material                                      Special-alloy cast iron

Intake valves
Disc diameter                                 32.4--32.6 mm (1.2756--1.2835")
Stem diameter                                 7.955--7.970 mm (0.3132--0.3138")
Valve seat angle                              45° 15' - 45° 45'
Cylinder head seat angle                      45°
Width of seat in cylinder head                approx 1 mm (0.040")
Clearance, hot engine                         0.30 mm (0.012")

Exhaust valves
Disc diameter                                 27.4-27.6 mm (1.0787--1.0866")
Stem diameter                                 7.950--7.965 mm (0.3130--0.3136)
Valve seat angle                              45° 15' - 45° 45'
Cylinder head seat angle                      45°
Width of seat in cylinder head                approx 1 mm (0.040")
Clearance, hot engine                         0.30 mm (0.012")

Valve guides
Length, intake valve                          38 mm (1 .4961")
Length, exhaust valve                         38 mm (1 .4961")
Bore                                          8.0--8.015 mm (0.3150--0.3156")
Height above cylinder head spring face        8.85--9.15 mm (0.3484--0.3602")
Clearance, valve stem-guide:
intake valve                                  0.03--0.06 mm (0.0012--0.0024")
exhaust valve                                 0.035--0.065 mm (0.0014--0.0026")

Valve springs
Length, off-load                                          42.5 mm (1.6732")
Loaded with 170±10 N (17±1 kp = 37.5±2 lbf)               32 mm (1.2598")
Loaded with 300±20 N (30±2 kp = 66±4.5 lbf)               24 mm (0.9449")

Lubricating system
Oil capacity, excl. filter                                2.8 litres (2.5 lmp.qts. = 2.9 US qts.)
Oil capacity, incl. filter                                3.0 litres (2.6 lmp.qts. = 3.2 US qts.)
Oil quality ace. to API-system                            CD (DS)
                         0   0
Viscosity, above +10 C (50 F)                             SAE 20 W
                         0  0
Viscosity, below +10 C (50 F)                             SAE 10 W
                                                                            2                  2
Oil pressure, hot engine, idling speed                    0.8--1.5 kp/cm (11 .4--21 .3 lbf/in )
                                                                           2              2
Oil pressure, hot engine, full speed                      3.5--4.0 kp/cm (50--57 lbf/in )

Reverse gear
Oil quality/Viscosity                                     Same as for engine
Oil capacity, din (qts.), red. 1:1                        0.4 (0.4)
Oil capacity, din (qts.), red. 1.91:1                     0.55 (0.5)

Combi reduction gear
Reduction gear                                            Same oil compartment as engine's
Reversing mechanism and propeller hub                     Lubricating grease Shell Alvania EP2 or similar

Lubricating oil pump
Type                                                      Gear wheel pump
Relief valve spring: Length, off-load                     45 mm (1 .7717")
Loaded with 15 N (1.5 kp = 3.3 lbf)                       40 mm (1.5748")
Loaded with 46 N (4.6 kp = 10 lbf)                        29 mm (1 .1417")
Axial clearance of gear wheels incl. gasket               0.048--0.084 mm (0.0020--0.0033")

Fuel system
Fuel injection pump, make Bosch (Up to engine no 19999)   0 460 302 008
Fuel injection pump CAV (From engine no 20000)            0 3222 F070
Injectors, make Bosch, holders                            0 431 112 001
Nozzles                                                   0 433 171 009
Hole diameter                                             Four 0.23 mm (0.0091")
                                                                           2                  2
Opening pressure                                          185--193 kp/cm (2631--2744 lbf/in )
Spray angle                                               150 C
Advance angle, Bosch pump                                 11°± 1° b.t.d.c.
Advance angle, CAV pump                                   14°± 0.1° b.t.d.c.
Injection quantity, Bosch pump                            18±0.5 mg/stroke at 43 rev/sec. (2580 rev/min)
Injection quantity CAV pump                               17.5±0.5 mg/stroke at 43 rev/sec. (2580

Feed pump
Type                                                      Pierburg PE 15672
                                                                          2                2
Feed pressure at 42 rev/sec (2500 rev/mm)                 0.65--0.85 kp/cm (9.2-12.0 lbf/in )

Electrical system
Battery voltage                                                 12 V
Battery capacity                                                Max. 120 Ah
Starter motor, Bosch                                            0 001 311 115
Starter motor output                                            1.1 kW (1.48 h.p.)
Alternator SEV Marchal                                          70 229712
Alternator output                                               490W 35A
Battery electrolyte specific gravity: Fully charged battery..   1.275--1.285 g/cm
When charging has to be carried out                             1.230 g/cm

Cooling system
Thermostat                                                      Bellows thermostat
                                                                  0       0
Starts opening at                                               60 C (140 F)
                                                                  0       0
Fully open at                                                   74 C (165 F)

Rebore for wear
    (or if engine has abnormal fuel consumption)                0.25 mm (0.010")

Main bearing and connecting rod journals
Permitted out-of-roundness                                      0.06 mm (0.0024")
Permitted taper                                                 0.05 mm (0.0020")
Max. axial play on crankshaft                                   0.40 mm (0.157")

Bearing journals, permitted out-of-roundness                    0.03 mm (0.0012")
Max. clearance between camshaft and bushings                    0.15 mm (0.0060")

Max. clearance between valve stem and guide                     0.15 mm (0.0060")
Edge of valve disc should be mm                                 1.0 mm (0.0400")

Tightening torques                                              Nm              Kpm    Lbf ft
Cylinder head nuts                                              70              7      51
Cylinder head stud bolts                                        20              2      14
Bolt for flange on crankshaft                                   70              7      51
Flywheel nut                                                    180             18     130
Connecting rod bolts                                            70              7      51
Water pump flange (Bosch fuel injection pump)                   60              6      43
Water pump flange (CAV fuel injection pump)                     80              8      58
Main bearings                                                   50              5      36
Nuts for fork for injectors                                     8               0.8    5.8
Bolt for intermediate gear transmission                         70              7      51
Starter motor bolt                                              70              7      51
Bolt, front engine mounting                                     45              4.5    33
Bolt, rear engine mounting                                      45              4.5    33

Tightening scheme for cylinder head nuts

     Longitudinal section   Cross section


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