John Deere 310A won't start

I am new to the world of diesel mechanics, but decided to jump in head-first. I recently bought a 1978 John Deere 310A and it will not start.

Some history on the machine (as I was told)
It was running "a few months ago", but had some coolant in the oil. The oil was changed and there was more coolant in it. After a pressure test on the radiator it was determined that it was likely a head gasket leak. They pulled the head off and found a burned spot on the gasket and no sign of cracks in...

John Deere 310A won't start