An update, I took the 50 out for some pre-start exercise/checkout and found something else that was stuck. Before pulling the tractor I set up a video camera on the oil pressure gauge to make sure that I had pressure. After a short distance of pulling when it should have picked up oil pressure, it had absolutely no pressure on the gauge, something was wrong there. Come to find out it seems that the last barnyard mechanic years ago had removed the oil pump cover and installed it with silicone sealer with no gasket. Needless to say the pump was stuck tight and the pump drive coupling was missing in action. I now have a new coupling and gasket ordered.

Luckily I had pumped about 1/2 gallon of motor oil into the pressure system during the process of freeing the engine. The engine bearings are and were well lubricated, even without a working oil pump.

The engine compression is picking up and I believe it is going to be a runner.