Well, I got it running yesterday, used an external gas tank gravity fed off the hood until I can be sure the fuel lines are clean. I pulled the line off the carb, found a brake line that matched the thread and line size, connected it and got fuel to the carb. I hooked up the battery with new cables after I cleaned off all the contact points until they were shiny bare metal, there is no key switch anymore on my tractor (if there ever was?)- just a push button and push/pull "run" switch. That push/pull switch is shot, corroded and frozen in place. I pulled it, quick connected all three wires on the back of it together, and started testing for power. I now had power to the coil, still no crank though.
I pulled the push-button switch out, removed the wires, crimped on new terminals, wire brushed the contacts on the switch, reassembled. Tested with an ohm meter, tested good after that. Press the button, starter kicks in and motor cranks! We've got fuel and air now! Getting close!
I had to pull the cap/rotor out and sand the contacts in the cap, file the points as there was no spark. I pulled all four plugs out and tried to crank it after putting just a touch of oil down each cylinder. I let it crank a bit until the oil pressure gauge (which still works!) moved up to 10psi. Time to fire this thing off! I tested for spark, got it! We've got fuel, air, and spark!
I gave it a shot of ether, choked it, pressed the start button- it coughed and sputtered to life! I have to order a carb rebuild kit, as I have to play the choke a bit to keep her going, but it runs pretty decent otherwise at 1/4 throttle. No smoke, doesn't smell overly rich even for just firing up. Suffice to say that I'm very happy. Now I'll pull all the old wiring and do a proper job at that with sealed connectors and good wire. You can tell an old farmer did this wiring on the fly. I'll also wire the lights mounted to the loader frame to a relay and run heavier wire to them as it's quite thin. Eventually maybe put some LEDs in for more light with less power consumption.
Problem: On the front left side, where the motor meets the transmission there is a hole large enough for me to fit my pinky in, maybe a bit bigger. When the tractor is running, oil (frothy, water mixed oil) comes out that hole. Is there supposed to be a plug there? Surely it's not supposed to puke oil- that scares me, as that's where I imagine the clutch is- looks like this is in the bellhousing. Did one of the internal seals fail and allow all that oil to get in there? If so, why did it not leak out the very bottom between the mating surfaces?
That being said, I'm planning on draining the engine oil, replace that, drain the transmission completely, put some diesel in it, run it back and forth a bit to flush it out, then drain overnight and refill. Definitely has water in it.