Chrisleasmith

I have a 1960s marine version of the ME Snipe. It is impossible to turn over unless I back off the cooling jacket. Also the piston seems to foul the top of the cylinder. The compression adjustment screw doesn’t have any effect. Am I missing something? Any advice would be appreciated. Chris

Marklubbock

Someone has probably turned the compression screw down too far at some point. The contra piston is quite a tight fit in the bore and is not actually connected to the screw, but relies on the piston or compression to move it up the bore. Try backing the compression screw completely off an carefully turn the engine. Th contra piston should back off but if you need excessive force it's probably best to remove the liner and manually force the contra piston back. A short length of rod or possibly a bolt slightly smaller than the bore and use a vice to push it back. Hope this makes sense and helps.

Chrisleasmith

Hi Mark,
thanks. Someone else suggested your solution and it worked perfectly. Now I’ve solved the problem I have sold the engine. Thanks for taking the trouble to reply.
Regards
chris