2hp overheated - stuck piston rings?

[pvcmsc]

I'm working on a 1977 2 hp johnson for a friend. Engine may have been ran hot, It's mildly discolored aound the exhaust/head. I checked the compression and it was 80 pounds. I have the same motor myself and it has 95# compression.

Once I saw a motor that had been hot and it had stuck piston rings. Since this motor had really low wear before the "incident" I wandered if there are any shade tree tricks or magic potions that may free a stuck piston ring???

Trust me - it has a new impellor now.

 

[OBJ]

Re: 2hp overheated - stuck piston rings?

Welcome to iboats pvcmsc!

How sure of ya' of the "low wear"? Do you know the compression before the incident? What you may try is, do a decarb and see if the compression improves. An engine can live through an overheat if it's not a prolonged overheat condition. Another thing to look at is the head gasket. Could have been damaged during the "incident". Also check the head for warpage.

 

[F_R]

Re: 2hp overheated - stuck piston rings?

It's easy enough to remove the exhaust cover and look. That would be the thin flat plate on the side of the cylinder. Overheat damage usually results in a scored piston, not just rings. But take a look-see.

Use a new gasket to reinstall that plate! If it leaks, it will squirt water into the exhaust ports.

 

[pvcmsc]

Re: 2hp overheated - stuck piston rings?

thanks for both replies - very much appreciated. As for known amount of wear - can't really say for sure, but it's a WV motor and typically they aren't used that much here. Plus paint looks good. Good point though - I could be dead wrong on usage.

If I decarb it and compression goes up - what does it tell me?

I'll do both the decarb and then remove the exhaust plate for a closer inspection.

 

[OBJ]

Re: 2hp overheated - stuck piston rings?

If you decarb and the compression goes up, it could be telling or pointing to some different things like: there has been to heavy a mix in the fuel with oil, the engine is running cold and not coming to temp, poor ignition spark at the plugs. Any of the above or a mix can cause rings to stick. Do the decarb and see what the compression does. Go from there. Let us know your progress.