I have pulled the pump and gone through all the valves and everything seems to be working as far as I can tell and nothing is missing. The tractor has been setting for several years but the engine has not been torn down at all. I do have low compression but it still starts and seems to run well. I did find some sludge in the bottom of the crankcase when I drained the new oil out that I had put in. I fear that the oil passages on the crankcase may be blocked with that sludge and I will have to tear the engine down.
Thx for your advice.