Small Engines (Lawn Mowers, etc.): 17.5 hp Kohler, compression stroke, hp kohler

Question
I wish I would have looked up my strange problem, to discover it is a common problem prior to ripping my engine to pieces.   My tractor sat for a couple of months and gas filled the engine.  Seeing now that it was a carb problem would have saved me a weekend worth of heartache.  Oh well, the issue is know the motor wont start.  I did get it running briefly after rebuilding it, but needed to shut it off to get it out of the garage.  After moving it out side I can no longer start it.  The starter will not advance the engine past the compression stroke.  I have removed the spark plug, and the starter "cranks" the engine fine.  Reinstalling the spark plug and the starter stops on the compression stroke.  The only thing from the engine that I removed was the head.  I did not remove the crank, cam, or flywheel from the engine.  It did start once.  Am I missing something?   I know my way around car engines, but this the first time I have pulled a small engine this far apart.

My thoughts are that the starter could be weak,  it was quite warm (hot to the touch) yesterday when I was using my car to jump start the tractor.  Or I some how got the engine 180 out, (but I wouldn't think it would run at all that way and I did have it running once.

Answer
Nope you did nothing wrong.  Of course you have learned the hard way about "hydro locking" or hydraulic lock.

It sounds like your valves need to be adjusted.  An improperly adjusted valve will give you this condition you are describing.  I dont have your model number so i cant tell you the valve clearence specs.

No worries.... youll get it figured out if you understand automotive engines.