I would suspect a blown head gasket.
You should be able to tell the bad cylinder by reading the spark plugs.
On the "bad" side, remove the valve cover.
With a rag handy, start the engine and look for a "mist" blowing out toward the push rod side.

no smoke at all.....makes me think its not the head gasket......but I'll pull the valve cover and check.....

I think I'll also give the carb a good cleaning....it needs it anyhow...

thks a bunch

here is another idea.

sometimes the intake valve guide gums up and the valve is slow to seat. The push rod falls out of position and you have a dead cyl.

if this is the case, the best prevention is better fuel quality. Non ethanol fuel if available is one choice. Use fuel preserver in your spare gas can - all the time.

To repair, some techs will spray the end of the valve stem with spray cleaner. This works for a while, but since the intake valve has a seal, the cleaner does not find a way to the guide. I pull the heads to remove the valve for more thorough cleaning.

I like to add some Marvel Mystery Oil to my fuel (along with Stabil) to make sure the fuel also provides some lube property to the intake valve stem ( which is exposed to the induction stream in the head).
I too am one of those who believe ethanol does much to aggravate formation of gummy deposits on the intake valve stem, which may stick the valve in place if the engine last stopped with the valve open.

thanks fellas.....I checked to make sure the piston is moving....and it is....so no broken rod...whew....but I haven't gone farther yet.

There's a bit of oil on the plug but not much....and there's a bit of oil underneath the valve cover....maybe a leaky gasket....I'll know tomorrow.....cant think of any other reason oil would collect there...unless its porting thru the carb somehow...

I'll pull the valve cover and check the pushrods to see if they're in place and go from there.

If they look good....I'll probably make sure the carb gets cleaned and eliminate a plugged barrel before I pull the head.

well well....it wasn't the head gasket.....turned out the push rods have gone on vacation.....

I imagine they are resting comfortably in the sump.......

I think a valve stuck....guides are in the right position...don't look like they migrated....

probably will replace the cylinder head after I split it and dig them out and check the cam.....maybe they fell thru unscathed.....but likely they are in pieces....

Motor sure runs smooth tho......best little 12 horse you ever saw right now!!