OverviewThe Gray Marine 4-112 engine in my Lapworth 36 is a gas powered engine typical of pre Atomic Four engines. After blowing a head gasket at 150 hours and paying $75 for a new one, I looked for parts for this engine.
Gray Marine 4-112This engine can be identified by the Y112 casting id on the head. It is based on a Continental Y112 which is used in fork lifts and tractors. That makes parts readily available as many of these are still in service. Interestingly, they are also used in welders. This short page documents some useful information.
Head GasketFel-Pro 7602 S-1 Cylinder Head Gasket is available on Amazon as of the time I wrote this for $26, about half what I paid.
Spark PlugsThe Gray Marine cross references list Champion D16 (516). The Continental Y112 lists D21(502) which is one hear range higher. I might consider trying the D21 for a bit less chance of fouling. My plugs never look like they are running hot. Here are a couple of handy references to help determine if plugs are too hot or too cold.
CarberatorThe Marvel Schebler Carburetor Manual is on L-36.com HERE.
ManualThe Maintenance Manual is on L-36.com HERE
Water PumpI have had good luck and bad luck with water pumps. The good luck was with Depco Pumps in Florida. The pump is a Sherwood Q10840. HERE is a pdf,
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The information on this web site has not been checked for accuracy. It is for entertainment purposes only and should be independently verified before using for any other reason. There are five sources. 1) Documents and manuals from a variety of sources. These have not been checked for accuracy and in many cases have not even been read by anyone associated with L-36.com. I have no idea of they are useful or accurate, I leave that to the reader. 2) Articles others have written and submitted. If you have questions on these, please contact the author. 3) Articles that represent my personal opinions. These are intended to promote thought and for entertainment. These are not intended to be fact, they are my opinions. 4) Small programs that generate result presented on a web page. Like any computer program, these may and in some cases do have errors. Almost all of these also make simplifying assumptions so they are not totally accurate even if there are no errors. Please verify all results. 5) Weather information is from numerious of sources and is presented automatically. It is not checked for accuracy either by anyone at L-36.com or by the source which is typically the US Government. See the NOAA web site for their disclaimer. Finally, tide and current data on this site is from 2007 and 2008 data bases, which may contain even older data. Changes in harbors due to building or dredging change tides and currents and for that reason many of the locations presented are no longer supported by newer data bases. For example, there is very little tidal current data in newer data bases so current data is likely wrong to some extent. This data is NOT FOR NAVIGATION. See the XTide disclaimer for details. In addition, tide and current are influenced by storms, river flow, and other factors beyond the ability of any predictive program.