10 hp tecumseh on a generator ran daily for two months until it developed a compression problem. Upon initial inspection I can see that the exhaust valve opens slightly then closes again during the compression stroke. I'm reluctant to tear into it until I have some idea what the problem could be.

spring may have popped off maybe, it doesn't come out maybe a cm and half or so?

I haven't removed the head. I removed a breather panel below the exhaust and intake manifold and can only see the middle of the valve shaft and the spring. Everything appears normal from there except that the valve opens, about a cm just after the intake valve closes. It opens quite a bit more then that during the normal exhaust stroke and then appears to close properly afterwards.

so the valves open and close about the same? what about the head check that for warpage if it even would have any and make sure the gasket looks pretty good. that'll eliminate a leaky head. about how old is it?

The exhaust valve should open that little bit on the compression stroke. That is the compression release. Just check the valve clearances and possibly pull the head to make sure the faces and seats look good. What is the cmpression showing on this engine? Has it been smoking?

Mike

10 hp tecumseh on a generator ran daily for two months until it developed a compression problem. Upon initial inspection I can see that the exhaust valve opens slightly then closes again during the compression stroke. I'm reluctant to tear into it until I have some idea what the problem could be.
thats the compression relese, thats normal :wave:

i thought it was something serious. valve don't open all the way. yeah that would be the compression release. unless it doesn't run right at all it may be broken etc.