Thornycroft 90 And 108 Workshop Manual
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Fpba8Nwf L9DFPAx01 3 Bpcw 1Ghr Lgo p f fsqv1 hcAsgoyj8o64s 0ny8W8sd8lG1A GAc s 981d x33p2cx pgOG0srKg6DG3k D1W BS 55141 MARINE ENGINES The Thornycroft 90 and 108 engines are both 4 cylinder 4 stroke naturally aspirated high speed diesel units both engines having electrically operated heater plugs to aid cold starting The cast iron crankcase with ribbed sidewalls houses a forged steel fully crankshaft carried in three or five bearings respectively A full pressure wet sump lubrication system is employed with a full flow detachable element type oil filter and integrated lubricating oil cooler The cooling system is indirect and usually employs an engine mounted heat exchanger with a belt driven raw water pump This system is known as IFWC internal fresh water cooled An optional system is EFWC external fresh water cooled This system utilizes the engine fresh water pump and usually employs skin tanks attached to the hull to serve as heat exchangers The single belt driven alternator and fresh water pump drive include a manual belt tensioning arrangement for low maintenance completes the comprehensive engine package 90 108 4 Cylinder naturally aspirated 4 Cylinder naturally aspirated Power intermittent at 3500rpm 36BHP Power intermittent at 3500rpm 47BHP continuous at 3000rpm 30BHP continuous at 3000rpm 38BHP Maximum torque at 2400rpm 731bf ft Maximum torque Idle speed at 2500rpm 531bf ft 570rpm Idle speed 570rpm Minimum full load speed 1500rpm ENGINE RATINGS Minimum full load speed 1500rpm The type 90 Engine may be set to develop continuous outputs from 135 to 30 BHP according to requirements The type 108 Engine may be set to develop continuous outputs from 21 to 38 BHP according to requirements For special applications where full power will not be required for periods in excess of 1 hour in any 12 hours consecutive running the engine can be supplied at an intermittent rating as shown above NOTE All horsepower ratings quoted are at the engine flywheel Due allowance must be made for transmission losses which will depend on the type of gearbox fitted For tropical use it is necessary to derate the engine by 2 for each 5260C 10260Fabove 30260C 85260F air temperature at sea level In some parts of the world further derating for humidity is necessary in accordance with INITIAL STARTING OF ENGINE PAGE Engine mounting and dipstick marking Filling engine with oil 2 Lubricant specification for engine and gearbox Filling gearbox 3 inhibitor specification Filling cooling system 4 Priming the engine oil system 5 Bleeding the fuel system type 90 engines 6 Bleeding the fuel system type 108 engines 7 Initial start Normal start Running in 8 Operating guidelines 9 Operating guidelines MAINTENANCE Maintenance schedule Engine oil and filter change Engine oil and filter change Fuel filter change Cleaning fuel lift pump Gearbox oil change Cleaning air filter Alternator drive belt adjustment and replacement Raw water pump adjustment and replacement Checking and setting valve clearances Procedure for retorquing cylinder head nuts fuel injectors Changing coolant Draining raw water system External fresh water cooled engines Electrical system Fault finding Fault finding Laying up the engine Notes 10 11 12 13 14 15 16 17 Type 90 engines Type 108 engines 18 19 20 21 22 23 24 25 26 27 28 29 THORNYCROFT Page 1 CHECKING ENGINE MOUNTING The maximum installed angle of the engine is 15260 engine types 902 108 and 1082 10260 for engine type 90 This allows for a further rise of 4260 when the craft is moving Check the angle of installation using the centreline of the mounting feet bolts as a datum Measure vertically on the centreline of the underside of the front mounting foot bolt to find the angle of installation Fig 1 Fig 1 Horizontal Line Type 90 Type 902 Type 108 A 93mm 10260 A 138mm 150 A 136mm 15260 46mm 5260 93mm 10260 91mm 10260 46mm 5260 46mm 5260 MARKING DIPSTICK FILLING WITH OIL Your engine is despatched from the factory without engine or gearbox oil and with an unmarked engine dipstick After the boat is launched and is resting at its normal trim angle remove the oil filler cap from the rocker box Fig 2 and pour 39 litres for type 90 45 litres for type 902 or 48 litres for type 108 of specified lubricant through the filler hole Allow 5 minutes for the oil to drain into the sump withdraw the dipstick and mark it for maximum oil level Fig 3 Use a centre punch for marking as filing a notch can cause fatigue and eventual breakage while the engine is running Then mark dipstick using the same method 127mm below the maximum mark and this will be the minimum level CHECKING ENGINE MOUNTING MARKING DIPSTICK FILLING ENGINE WITH OIL LUBRICANT ENGINE AND GEARBOX Page 2 ENGINE OIL RUNNING IN OILS Do NOT use special runningin lubricating oils for new or rebuilt engines Use the lubricating oils specified for normal engine operation ENGINE OIL VISCOSITY The use of a multigraded lubricating oil has been found to improve oil consumption and improve engine cranking in cold temperatures while maintaining lubrication at high operating temperatures A multigrade oil conforming to MILL20104B is recommended with the viscosity grades shown in Fig 4 The use of single grade lubricating oil is not recommended except for synthetic oils used in arctic conditions Atmospheric Temperature Viscosity Above 10260C 20W50 20260C to 10260C 1OW30 or 1OW40 Below 10260C 5W30 or 5W40 Fig 4 GEARBOX OIL Borg Warner Automatic Transmission Fluid Type AHurth Automatic Trnamsission Fluid Type ANewage PRM SAE 20 Engine Oil Minus 18260C to 0260C SAE 30 engine Oil Above 0260C FILLING THE GEARBOX Remove the oil filler plug combined dipstick from the top of the gearbox This is in approximately the same position on Hurth Newage PRM and Borg Warner Using a plastic bottle or funnel fill the gearbox up to the maximum mark on the dipstick There is one level mark on the Hurth dipstick the others have high and low marks THORNYCROFT Fig 5 M Fig 8 COOLING SYSTEM Page 3 COOLANT Use antifreeze during all seasons to protect the engine cooling system from corrosion as well as freeze damage Using the following antifreeze solution 25 33 50 Solution Solution Solution Complete protection lO260F12C 3260F16C protection 1260F17C 8260F22C 18260F28260CIn tropical climates where antifreeze availability may be limited corrosion inhibitor to protect the engine cooling system NOTE Corrosion inhibitor is NOT an antifreeze COOLANT QUANTITIES Complete system including engine IFWC types 90 and 108 engines 51 Litres For external fresh water cooled engines EFWC See Page 23 FILLING THE COOLING SYSTEM Remove the filler cap from the heat exchanger Fig 6 and fill the system with coolant This will take approximately 5 minutes as the system self bleeds Fill to 5mm below the filler neck level mark Refit filler cap THORNYCROFT use a M Fig 9 405i l I Page 4 PRIMING THE ENGINE OIL SYSTEM TYPE 902R ENGINES ONLY As only a residual amount of oil is present in the oil pump filter and oil galleries of the engine it is therefore necessary to prime the system before the engine is run Connect the engine starter batteries disconnect power to the fuel solenoid valve on the injection pump Fig 7 and crank the engine over using the key starter switch until pressure registers on the oil pressure gauge Stop cranking and check the engine and gearbox for oil or water leaks Replace power connector Fig 7 PRIMING THE ENGINE OIL SYSTEM TYPE 90 AND108 ENGINES As only a residual amount of oil is present in the oil pump filter and oil galleries of the engine it is therefore necessary to prime the system before the engine is run Connect the engine starter batteries operate the key starter switch with the stop control out crank the engine over until pressure registers on the oil pressure gauge Stop cranking and check the engine and gearbox for oil or water leaks PRIMING THE ENGINE OIL SYSTEM THOMYCWFT Page 5 BLEEDING THE FUEL SYSTEM Slacken the bleed valve on the injection pump Fig 8 Operate the lift pump Fig 9 and when the fuel coming from the valve is free of air bubbles tighten the valve Fig 8 Slacken the unions at the injector ends of any two high pressure pipes Fig 10 Ensure that the stop control is in the run position and the engine speed control is in the fully open position Crank the engine until the fuel coming from both pipes is free from air bubbles then tighten the unions NB After initial start procedure has been observed start the engine and allow it to idle until it is running evenly on all four cylinders THORNYCROFT BLEEDING THE FUEL SYSTEM TYPE 90 ENGINES Fig 10 Fig 13 BLEEDING THE FUEL SYSTEM 5 3 Fig 11 2 46 Note After renewing the fuel filter element it will only be necessary to bleed the fuel filter as described in 1 and 2 provided that the engine has not been cranked while the filter is dismantled 1 Slacken the blanking plug in the unused outlet connection in the fuel filter head Fig 12 Operate the lift pump Fig 9 page 5until the fuel flowing from the plug is free of air bubbles tighten the plug NB Numbers 26 refer to Fig 11 bleed points 2 Slacken the union nut at the injection pump end of the fuel feed pipe Operate the lift pump and when the fuel flowing from the union is free from air bubbles tighten the nut 3 Slacken the air bleed screw on the injection pump body Operate the lift pump and when the fuel flowing from the bleed screw is free from bubbles tighten the screw 4 Slacken the air bleed screw on the injection pump governor housing Operate the lift pump until the fuel flowing from the bleed screw is free from air bubbles leave the bleed screw slack 5 Slacken the air bleed screw on the injection pump high pressure banjo bolt Operate the starter motor while operating the throttle control and when the fuel flowing from the high pressure bleed screw is free of air bubbles tighten the bleed screw 6 Continue cranking the engine with the starter motor to expel any air trapped in the governor and when the fuel flowing from the governor housing bleed screw is free of air bubbles tighten the screw Slacken the unions at the injector ends of any two high pressure pipes Fig 13 Ensure that the stop control is in the run position and the engine speed control is in the fully open position Crank the engine until the fuel comibng from both pipes is free from air bubbles then tighten the unions NB After initial start procedure has been observed start the engine and allow it to idle until it is running evenly on all four cylinders BLEEDING THE FUEL SYSTEM TYPE 108 ENGINES THORNYCROF Fig 12 THORNYCROFT Page 7 INITIAL START With all systems filled primed and checked the engine may be started Run it for 2 to 3 minutes then stop it Top up engine gearbox oil and water levels to the high mark The engine and gearbox are now ready for use Oil pressure should be observed within 15 seconds NORMAL STARTING PROCEDURE 1 Put gearbox selector lever in neutral 2 Ensure the stop control is fully disengaged 3 Set the engine speed control lever fully open 4 Turn the key to H position on starter switch and hold for 30 seconds this preheats the heater plugs This is not necessary for a warm engine Also control level only needs to be set half open5 Turn the key to H S position and the starter motor will crank up the engine CAUTION If the starter fails to crank up the engine within 10 seconds release the switch key and wait for the starter motor to come to a complete stop Then turn the key to H S position again Do not engage the starter motor for more than 30 seconds then wait 2 minutes between unsuccessful attempts 6 Move the throttle position to idle as soon as engine starts 7 Oil pressure should be observed within 15 seconds 8 To stop the engine pull the stop control RUNNING IN The care given to an engine in the first 20 hours of operation will result in longer life better performance and more economical operation During this period follow these 1 Warm up the engine before placing it under load 2 Do not operate the engine at idle or full load for more than 5 minutes 3 Avoid constant speed 4 Observe oil pressure and temperature gauges 5 Check the oil and coolant levels frequently GENERAL PRECAUTIONS 1 NEVER attempt to start the engine with the gearbox control lever in any position other than neutral 2 NEVER stop the engine without first engaging neutral 3 When changing the control lever from ahead to astern or vice versa pause in neutral INITIAL START NORMAL START RUNNING IN I Page 8 COMPLIANCE WITH THE FOLLOWING CAN RESULT IN LONGER LIFE BETTER PERFORMANCE AND MORE ECONOMICAL OPERATION OF YOUR ENGINE Routinely perform all of the specified maintenance including the First Start of the Day checks Use antifreeze during all seasons to protect the cooling system from corrosion as well as freeze damage Never operate the engine without a thermostat Use quality fuel that is free of water and other contaminants Monitor the oil pressure and temperature indicators frequently AVOID FULL THROTTLE OPERATION WHEN THE ENGINE IS COLD When starting a cold engine bring the engine up to operating speed slowly to allow the oil pressure to stabilise as the engine warms up If temperatures are below 0260C 32260Foperate the engine at moderate speeds for 5 minutes before full loads are applied AVOID IDLING THE ENGINE FOR MORE THAN 10 MINUTES Long periods of idling may be harmful to your engine because combustion chamber temperatures can drop so low that the fuel may not burn completely Carbon can then form which may clog the injector spray holes and also cause valves and piston rings to stick AVOID OVERHEATING THE ENGINE Coolant temperature must not exceed 99260C 210260F with a 70 kPa 10 psiexpansion tank cap AND A MINIMUM OF 50 mixture of ethyleneglycol and water IDLE THE ENGINE A FEW MINUTES BEFORE ROUTINE SHUTDOWN After full load operation idle the engine 3 to 5 minutes before shutting it off to allow the lubricating oil and coolant to carry heat away from the combustion chamber bearings shafts etc AVOID LOW COOLANT TEMPERATURE OPERATION Continual operation at low coolant temperature below 60260C 150260Fharmful to the engine Low coolant temperature can cause incomplete combustion allowing carbon and varnish to form that can damage piston rings and Also the unburnt fuel can enter the crankcase diluting thelubricating oil causing rapid wear to other moving parts OPERATING GUIDELINES THORNYCROFT Page 9 DO NOT OPERATE THE ENGINE WITH LOW OIL PRESSURE When the engine is at normal operating temperature the minimum oil pressures required are Idle 570 RPM 1 bar 15 psiFull Speed and Load 23 bar 35 psi DO NOT OPERATE THE ENGINE WITH FAILED PARTS Practically all failures give some warning before the parts fail Be on the alert for changes in performance sounds and visual tipoffs that indicate either service or repair is needed Some important clues are Engine misfiring or vibrating severely Sudden loss of power Unusual engine noises Fuel oil or coolant leaks Sudden change in the engine operating temperature Excessive smoke Loss of oil pressure SAFETY PRECAUTIONS Safety is built into every engine however like any other mechanical device it can present serious threat to life and limb if imprudently operated and maintained Remember that the best safeguards against accidents are to keep ever mindful of the potential dangers and to always use good common sense THORNYCROFT OPERATING GUIDELINES DAILY OR EVERY 10 HOURS Check engine and gearbox oil levels top up if necessary Check coolant level and top up if necessary Check drive belt tensions AFTER FIRST 25 HOURS Retorque cylinder head nuts Change the engine oil and renew engine oil filter Check valve rocker clearances Check drive belt tensions Check oil connections for leaks Check water hose connections Check all electrical equipment Change fuel filter element Check and service injectors as necessary Check and adjust engine idling speed as necessary Use a Thornycroft dealer Check fuel system for leaks ENGINES IN REGULAR USE EVERY 50 HOURS Check electrolyte level in batteries EVERY 200 HOURS OR YEARLY Change fuel filter element Change engine oil Change engine oil filter Check drive belts Check air cleaner and clean if necessary Check for oil or coolant leaks Check fuel system for leaks Check gearbox oil level Check and adjust idling speed as necessary EVERY 400 HOURS In addition to the 200 hour maintenance schedules change the gearbox oil Remove heater plugs and remove carbon from each orifice EVERY 800 HOURS In addition to the 200 hour and 400 hour maintenance schedules Adjust valve rocker clearances Test injectors for spray Use a Thornycroft dealerCheck all engine and gearbox connections Renew oil filler cap on rocker cover ENGINES USED OCCASIONALLY HALVE THE HOURS RECOMMENDED AFTER FIRST 25 HOURS MAINTENANCE SCHEDULE TH0RNYCROFT Page 10 THORNYCROFT Page 11 CHANGE ENGINE OIL Run the engine until it reaches normal operating temperature stop the engine then using the hand pump Fig 14 drain the oil into a suitable container Fig 14 CHANGE ENGINE OIL FILTER Slacken the centre fixing bolt 1 Fig 15 and withdraw the filter bowl 2 and filter element 3 together Discard the filter element and ENGINE OIL CHANGE TYPE 90 ENGINES sealing ring 4 Replace with new element and sealing ring ensuring that the ring is correctly seated in the filter head 5 and tighten the centre bolt Fill the engine with the specified amount of oil and prime the oil system as described on Page 4 Start the engine and check for oil leaks run the engine for 2 minutes ensure pressure registers on the gauge Stop the engine and allow a few minutes for oil to settle Check oil level top up if necessary Fig 15 Page 12 CHANGE ENGINE OIL Run the engine until it reaches normal operating temperature stop the engine then using the hand pump Fig 16 drain the oil into a suitable container Fig 17 Unscrew the oil filter cartridge Fig 17 Discard the cartridge and its sealing ring Lightly smear the sealing ring with clean engine oil Fig 18 and screw the filter cartridge into place using hand pressure only until the sealing ring abuts with the filter head face Then tighten a further a of a turn Fill the engine with the specified amount of oil and prime the oil system described on Page 4 Start the engine and check for oil leaks run the engine for 2 minutes ensure ENGINE OIL CHANGE TYPE 108 ENGINES THORNYCROFT as pressure register on the gauge Stop the engine and allow a few minutes for Oil to settle Check oil level and top op if necessary THORNYCROFT Page 13 RENEW FUEL FILTER ELEMENT Turn off the fuel supply tap then support the filter base 1 Fig 19 and unscrew the centre bolt 2 Detach the base and twist the element 3 to separate it from the filter head 4 Remove the three sealing rings 5 from the head and base Discard element and sealing rings Clean base and head and assemble the filter using a new element and sealing rings Fit the element with its strengthened rim uppermost Turn on the fuel supply tap then bleed the air from the system as described on Page 5 or 6 FUEL FILTER CHANGE Fig 19 Page 14 FUEL LIFT PUMP FILTER Turn off the fuel supply tap then remove the cap screw 1 Fig 20 Lift off the cap 2 gasket 3 and filter gauze 4 Clean the gauze in a suitable solvent using a stiff brush Clean the fuel chamber 5 Check that the gasket is serviceable or renew Assemble the components Do not overtighten the cap screw Never clean inside fuel chamber or any other part of the fuel system with a fluffy cloth Turn on the fuel supply tap then bleed the fuel system as described on Page 5 or 6 CLEANING FUEL LIFT PUMP THORWCT Fig 20 Fig 26 Page 15 CHANGING THE GEARBOX OIL The gearbox oil must be changed when the gearbox has reached operating temperature After about 12 hour driving the craft To help the oil drain easily from the gearbox first remove the oil filler dipstick plug from the top of the gearbox Place a suitable container under the gearbox and remove the drain plug from the underside of the gearbox and allow the oil to drain completely Fig 21 The drain plug is in approximately the same position on the underside of Hurth Borg Warner and Newage PRM gearboxes Refit the drain plug Fill the gearbox to the maximum mark on the dipstick Refit the filler plug start the engine in neutral and run the engine for 1 minute to allow the oil to circulate Stop the engine and check the oil level Top up if necessary to the maximum mark on the dipstick THORNYCROFT GEARBOX OIL CHANGE Fig 27 Illustration shows PRM 160 gearbox CLEANING AIR FILTER Page 16 CLEANING AIR FILTER Slacken the clip on the breather pipe and pull the pipe off the air cleaner then slacken the screw Fig 22 this allows removal of the outer casing and the air filter gauze Submerge the casing and gauze in a bath of clean paraffin or diesel fuel agitate them vigorously to remove dirt particles Shake the filter dry by hand or blow dry with compressed air then refit Fig 22 THORNYCROFT CAUTION WHEN USING A COMPRESSED AIR LINE GREAT CARE MUST BE OBSERVED AND GOGGLES MUST BE WORN Page 17 SAFETY BEFORE ATTEMPTING THESE OPERATIONS DISCONNECT THE STARTER BATTERIES Adjusting Alternator Drive Belt Type 90 alternator is shown in the illustration Fig 23 but procedure for adjusting the alternator drive belt is the same for type 108 engines Slacken the nuts and bolts 14 Move alternator away from the engine until the deflection of the belt arrowed is 19mm 075 in when pressed using finger pressure only at the longest point between pulleys Excessive tension will cause early wear of the belt water pump bearing and alternator bearing While a slack belt will slip causing overheating of the engine and insufficient charging of the batteries Check deflection after retightening Replacing Alternator Drive Belt Slacken the nuts and bolts Fig 23 14 move alternator in towards engine Remove old belt from pulleys and replace with new drive belt Retighten nuts and bolts Following the instructions above readjust the drive belt tension Fig 23 Adjusting Raw Water Pump Drive Belt Slacken the nuts and bolts Fig 24 1 and 2 and retension the belt as described above for the alternator The deflection of the belt must be 1012mm 039047in Check deflection after retightening Replacing Raw Water Pump Drive Belt Slacken the nuts and bolts Fig 24 1 and 2 Move pump in towards engine Remove old belt from pulleys and replace with new drive belt Retighten nuts and bolts following the instructions above readjust the drive belt tension Fig 24 THORNYCROFT DRIVE BELT ADJUSTMENT AND REPLACEMENT ALTERNATOR AND RAW WATER PUMP Page 18 SAFETY BEFORE ATTEMPTING THIS OPERATION DISCONNECT THE STARTER BATTERIES Setting Valve Clearances Engine Cold Slacken the rocker cover bolts and remove rocker cover Discard the gasket Turn the crankshaft in the normal direction of rotation and adjust as follows Slacken the locknut and adjust with a screw driver until the correct clearance is obtained Fig 25 Insert the feeler blade between the valve stem and rocker arm When correct adjustment is obtained the feeler blade is able to be removed with slight resistance Adjust in the following sequence Set No 1 tappet with No 8 valve fully open Set No 3 tappet with No 6 valve fully open Set No 5 tappet with No 4 valve fully open Set No 2 tappet with No 7 valve fully open Set No 8 tappet with No 1 valve fully open Set No 6 tappet with No 3 valve fully open Set No 4 tappet with No 5 valve fully open Set No 7 tappet with No 2 valve fully open Recheck the clearance with the locknuts tightened and readjust if necessary Fig 25 Valve Clearance Type 90 engines Inlet Valve 0381mm 0015inExhaust Valve 0381mm 0015in Valve Clearance Type 108 engines Up to Thornycroft Engine No 6043 Inlet and Exhaust 043mm 0017in Engine No 6043 onwards Inlet and Exhaust 035mm 0014inFit the rocker cover using a new gasket Tighten the bolts Reconnect the battery start the engine and check the rocker cover for leaks CHECKING AND SETTING VALVE CLEARANCE THORWCWFT Page 19 1 PROCEDURE FOR NEW ENGINES WHICH HAVE RUN FOR 25 HOURS A Run engine and stop when normal operating temperature is reached B Slacken the cylinder head nuts by approximately 16 of a turn one flat of the nut following the sequence shown using service tool 18G 1457 to reach the nuts in the centre row Fig 26 I C Tighten the nuts in the sequence shown to 104 kgf m 75 lb ft THORNYCROFT PROCEDURE FOR RETORQUING CYLINDER HEAD NUTS 11 6 5 12 00 00 0o 1 90 09010A OQ 14 107 3 1 4 89 13 p 0wxpx 30pxx x xx8f Slacken the valve rocker pedestal nuts by 16 of a turn one flat of the nut and retorque to 35 kgf m 25 lb ft Adjust valve rocker clearances Page 182 PROCEDURE WHERE PART ENGINES HAVE BEEN FITTED OR WHERE CYLINDER HEADS ARE REMOVED OR REPLACED DURING REPAIR OPERATIONS A The cylinder head nuts should not be more than finger tight until the rocker shaft assembly has been fitted B Tighten the nuts to 104 kgf m 75 lb fte 108 engines 98 kgf m C D When the 71 lb ft type 90 engines in the sequence shown in procedure Using service tool 18G1457 to reach centre row Fig 27 Tighten the valve rocker pedestal nuts to 35 kgf m 25 lb ft Adjust the valve rocker clearance as in procedure 1 engine has run for Y2 hour carry out the operation described 1 in procedure 1 Fig 27 THORNYCROFT Page 20 REMOVING FUEL INJECTORS Injector cleaning and spray testing can only be carried out with specialised equipment therefore this must be done by a Distributor or Dealer Fig 28 Disconnect the feed pipe 1 and spill rail 2 Note the sealing washers 3 on each side of the spill rail banjo union Remove the injector securing bolts 4 and withdraw the injector Fit protective caps to all open connections Fig 28 REFITTING FUEL INJECTORS Remove protective caps Ensure the washers are fitted to the injectors as shown in Fig 29 It is most important to tighten the injector fixings evenly and to the correct torque of 165 kgf m 12 lbf ft overtightening or uneven tightening of the injector can distort the nozzle and will usually cause a misfire to occur when normal running temperature is reached Reconnect the injector pipes do not overtighten the unions TO REMOVE HEATER PLUGS AND CLEAN ORIFICES Disconnect the battery Remove electrical leads 1 Fig29A and unscrew each plug 2 from the cylinder head Insert a twist drill of 437mm 1164india 3 into the threaded holes in the head 4 Turn the drill by hand to remove carbon buildup Remove the drill and clean any particles of carbon from conical seatings in the cylinder head Refit the heater plugs and electrical leads Reconnect the REMOVAL AND REFITTING FUEL INJECTORS Fig 29 battery Fig29A CHANGING COOLANT Page 21 CHANGING COOLANT Remove filler cap from heat exchanger place a suitable container beneath the drain plug Fig 30 Remove plug and allow to drain Place suitable container beneath drain tap in cylinder block Fig 31 Remove tap and allow to drain Replace both plug and tap then refill with coolant of the correct strength for conditions TAT to be encountered See Page 3 Fig 30 i Fig 31 DRAINING RAW WATER SYSTEM Page 22 DRAIN THE RAW WATER SYSTEM Slacken the six screws Fig32 on the raw water pump Remove end covers from heat exchanger and drain tubes either by removing the tube stack or by blowing out with compressed air Remove oil cooler and drain tubes or blow out with compressed air Alternatively disconnect raw water pipework before gearbox oil cooler and pipe from oil cooler into a container of antifreeze mixture and flush through system returning antifreeze mixture from water injection bend back into container this ensuring that any water pockets contain antifreeze NOTE ANTIFREEZE MIXTURE MUST BE OF CORRECT STRENGTH FOR CONDITIONS TO BE ENCOUNTERED Fig 32 CAUTION WHEN USING A COMPRESSED AIR LINE GREAT CARE MUST BE OBSERVED AND GOGGLES MUST BE WORN ROUTINE MAINTENANCE OF RAW WATER SYSTEM IFWC THESE NOTES DO NOT APPLY TO EXTERNAL FRESH WATER COOLED ENGINES Examine and clean the sea inlet strainer at regular intervals Do Not remove the strainer when the engine is running as foreign matter can be drawn into the system and cause irreparable damage to the pump The sea cock must be FULLY OPEN when the engine is running If the sea cock is partially closed air can be drawn in with consequential failure of the raw water pump and engine overheating Check the raw water discharge pipe immediately after starting the engine to see if the raw water pump is functioning The engine MUST NOT run without a flow of raw water through the heat exchanger RAW WATER PUMP the raw water pump is self priming and fitted with a neoprene impellor It depends on the raw water for its lubrication DO NOT run dry More than 30 seconds running without water will burn the impellor and be contributory to an early failure When replacing the end cover gasket it is essential to use the correct part variation of the gasket thickness can cause loss ofself priming ability or seizure Page 23 This consists of a closed circuit fresh water system with a fresh water circulator combined header tank and exhaust manifold dry exhaust outlet and watercoolant tanks normally fitted to the skin of the craft It is therefore important when filling this system with antifreeze solution or corrosion inhibitor that the total capacity of the tanks associated pipework and the engine cooling system is taken into consideration Your boat builder will advise you on these figures We have included the box below for you to fill in these figures for your craft THORNYCROFT EXTERNAL FRESH WATER COOLED ENGINES ONLY EFWC Name of Craft External Fresh Water Cooled System Capacity Date Change Due ELECTRICAL SYSTEM Page 24 Electrical System An insulated return system is employed on the type 90 and 108 engines The 12 volt alternator has a builtin voltage regulator which automatically adjusts the charging rate to provide sufficient electric current to keep the battery fully charged under normal operating conditions The alternator requires no lubrication maintenance Do NOT disconnect the battery leads while the engine is running Ensure that the correct battery terminal is connected to a good earth on the starter A coating of a good grade of petroleum jelly will protect the terminals from corrosion The electrolyte level should be 6 to 9mm 025 to 038in above the top of the plates If the electrolyte is below the correct level add the required amount of distilled water Distilled water for battery use should be kept in clean covered noncorrodible vessels In cold weather add water only immediately before running the engine so that the charging will mix the water and electrolyte and prevent freezing If the battery is allowed to stand at low temperatures in a partially discharged condition there is a possibility that it may freeze causing damage to the container Take care therefore to keep the battery as fully charged as possible The specific gravity of the electrolyte when the battery is fully charged should be 1275 at a temperature of 25260C 77260F At differing temperatures the specific gravity of a fully charged battery will change The specific gravity of any given temperature can be calculated by subtracting 0004 from 1275 for every 6260C change above 25260C and adding 0004 to 1275 for every 6260C below 25260C Keep the battery filler plugs and connections tight and the top of the battery clean Wiping the battery with a rag moistened with ammonia will counteract the effect of any of the solution which may be on the outside of the battery Wear protective goggles when carrying out this operation If ammonia is accidentally splashed in the eyes wash out thoroughly at once with clean water and SEEK QUALIFIED MEDICAL ADVICE IMMEDIATELY Using Jumper Cables To avoid the possibility of extensive damage to your charging system it is important to observe the following points when using battery jumper cables to start an engine having a discharged battery The positive terminals of the batteries must be connected through one cable usually red and the negative terminals connected through the other cable If this procedure is not followed extensive damage may be done to the charging system CAUTION Since explosive hydrogen gas is always present sparks or flames should not be allowed near the battery When using jumper cables the cables should always be attached to the booster battery first THORNYCROFT Page 25 FAULT FINDING ENGINE WILL NOT START Starter does not ELECTRICAL FAULT crank engine Battery run down Lead disconnected Faulty starter switch Faulty starter motor Starter cranks ELECTRICAL FAULT engine slowly Battery partly run down Terminals loose Connections dirty Faulty starter motor MECHANICAL FAULT Wrong grade engine oil Starter cranks ELECTRICAL FAULT engine normally Faulty glow plugs Faulty wiring connection MECHANICAL FAULT Injection timing incorrect Poor cylinder compression Blocked air intake FUEL FAULT Fuel Not Reaching Injection Pump Insufficient fuel in tank Blocked fuel pipeline Blocked fuel tank vent Restricted fuel filter Air leaks in pipeline Fuel Reaching Injection Pump Air in fuel system Faulty injectors THORNYCROFT FAULT FINDING
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