It's ALIVE!
So, with my last post, I noted that I changed the cylinder head gasket, and was having trouble getting the fuel lines primed after putting it all back together.
I only get to work on the tractor on the weekends, so there is a long wait between discovering an issue and having a chance to do anything about it unfortunately. The nearest IH dealer is 5 miles from my house, but 55 miles from where the tractor is! So needing a part and getting it has a 1 week turn around. The local autoparts place has been good for generic stuff though.
With Ken's advice, and my new GSS1271 "Fuel System" service manual, I bled out the fuel system. I discovered that I had a missing gasket on the pre-combustion chamber of the front cylinder, so I corrected that. That still didn't do the trick because I couldn't get the engine to rotate fast enough while cranking to actually start, even with a jump from a vehicle. Something was loading down this tractor's electrical system!
Well, this Saturday I discovered that the tractor has a second battery! I replaced this battery (the primary one was already replaced a few weeks ago). I left them on a trickle charger overnight, and left the block heater plugged in (despite temps being around 70 degrees in the mornings.
Sunday morning... 20 seconds of glow-plug, and she fired right up! Sounds like a brand new tractor. Runs like a charm, with no visible exhaust under load.
Ran it for a good part of the day on Sunday, and I couldn't be happier with it!