Got the wiring harness routed correctly, replaced the starter solenoid, installed the voltage regulator, starter generator, and replaced the key switch last Friday.
Since I wasn't confident in how clean the fuel tank was at the time, I used an old bottle for the first starting attempt. After filling the engine with oil and setting the choke, the 241 fired off for the first time in nearly 2 decades after only about 4 seconds of cranking. No drama at all
After the fact, (and the attached obligatory video) I used a siphoning blow gun to spray out the inside of the fuel tank with some diesel fuel one final time before installing it with a screw-in fuel filter attached (for now) so I could actually run the engine for a longer time.
I hooked the throttle cable up and ran the engine long enough to see that the head gasket had sealed, the charging system was functioning, and that the clutch was working as it should. It ran long enough to burn the leftover penetrating oil off with no issues that I could find.
Need to finish painting the front wheels, get a proper seat bracket, order some new rear tires, and change the differential fluid before the first test drive.
Also definitely need to find a muffler. For the sake of the operator and any other living thing within 100 yards of this engine while it's running
