With 'stuck' components, sometime all thats needed is to 'soak' the engine internals with MMO --- Marvel Mystery Oil. This is how 'junkyard' engines are brought back to life after long standing idle. The 'soak' frees up stuck piston rings, cleans out fouled piston ring grooves and 'rusty' valve stems, etc.
For a detailed description of how to 'soak' an engine go to: www.moyermarine.com and do a forum search for "MMO + spa" ... such will describe how once the engine is validated to be 'free' how to 'repolish' all the engine 'internals' using MMO and without engine disassembly. Do the leak down test to avoid a lot of 'guesswork'.
Most of internal engine problems on small marine diesels are the result of a leakey exhaust / manifold system that allows raw cooling water to get into the combustion chamber(s); so, if there is evidence of repair or replacement of 'exhaust' components, suspect that the engine has some level of internal rust, and that rust is preventing the face to face metal sealing components from working properly. If not too badly rusted can be 'repolished' using Marvel Mystery Oil, etc. and without tearing apart the engine.
For a detailed description of how to 'soak' an engine go to: www.moyermarine.com and do a forum search for "MMO + spa" ... such will describe how once the engine is validated to be 'free' how to 'repolish' all the engine 'internals' using MMO and without engine disassembly. Do the leak down test to avoid a lot of 'guesswork'.
Most of internal engine problems on small marine diesels are the result of a leakey exhaust / manifold system that allows raw cooling water to get into the combustion chamber(s); so, if there is evidence of repair or replacement of 'exhaust' components, suspect that the engine has some level of internal rust, and that rust is preventing the face to face metal sealing components from working properly. If not too badly rusted can be 'repolished' using Marvel Mystery Oil, etc. and without tearing apart the engine.