I did have it in the back of my mind that it would be the piston rings
but I thought that I would listen to a few comments first. Thanks
everybody! I didn't do a compression check and now the head is off,
but there didn't seem to be any loss of power when it was running.
Also, it shut down just fine and hasn't run away. I don't see any
signs of blow by in the intake or filter, but i do think that there is
a hint of diesel in the oil. There is a bit of black on top of the
cylinder heads. I think I'm going to replace the piston rings. I'll
post the results when finished.