Well, the thing was so dirty, I really couldn't even see what was underneath all the oil and dirt. So a few hours here and there with a scraper, several gallons of Super Purple cleaner, and finally a pressure washer revealed a tractor under that crap. Turns out it is yellow!
I did all this while the carb spent a week or two in the carb cleaner bucket. As mentioned, I had also squirted a healthy dose of oil down each cylinder just to make sure nothing would stick. Finally, after several weeks, I had time to mess with it one day, and decided it was time to see if it would turn over by hand. Low and behold, it spins nice and easy! So then I decided to see if it would turn over with the starter. So with the plugs removed, I hooked up a battery and gave it a whirl. Like I had hoped, it turned over easy and squirted whatever excess oil that was still in the cylinders out the hole. Then, as I was cranking it over, I put a finger over each plug hole as just a rough measure to check compression. All seemed functioning except for number two-which was sucking AND blowing with EVERY stroke. Oh-oh... I was afraid that that might be the end of the whole project right there.
I removed the valve cover to discover this-
Well. THAT can't be good! But the push rod appeared to be straight, the valve easily compressed with light tapping with a rubber mallet, and everything seemed OK. So, with the hopes that perhaps the valve had stuck when we first turned it over, and the extra-loose valve lash just allowed the push rod to fall out, we compressed the spring and stuck the push rod back under the rocker. With fingers crossed, I hit the starter and spun her over a bit (at this point, the carb is still in the cleaner bucket), and it seemed to function just fine.
Then I tightened up the valve lash a bit.
One thing I was concerned with, was during all our cranking activities, I never saw the oil pressure gauge so much as twitch. And after a LOT of cranking, there was only the barest hint of oil showing up at the push rods or in the head area. So I cracked the oil line to the guage and cranked away. Oil started dribbling out of the fitting-so we were getting flow there, at least-although it was not much. A quick squirt of air to the oil gauge line confirmed that the mechanical gauge worked. So I was pretty concerned.
I then decided to dump the old sludge out of the motor and change the filter-which I had ordered from Stieners. I say sludge, because the crap that was in that poor motor could not possibly have been motor oil. I think that oil had not been changed in decades. Then I poured some diesel down the head and out the pan in attempt to flush out any nasties. Then I put new oil in it. When I went to put the new filter on, I encountered the next issue-the filter they sent me was NOTHING like the one that came out of the canister! Luckily, there was a legible (Donaldson, I think) part number on it, and by some great miracle the local NAPA had one that crossed to it. With all that out of the way, it was time to get back to the carb...