Wouldn't look like this one, would it?
Purchased in ~1961. Have used it strictly for mowing and raking hay -- usually has the sickle-bar side-mounted mower attached.
Sold it a while back -- was still running great.
Recently had an issue on an IH carb on one of our other older tractors -- rubber needle-seat on carb had disintegrated, causing the motor to run rich and load up, surging and puffing black smoke out of exhaust stack -- likely the new gas/alcohol mix finally dissolved the older rubber needle valve material -- IH has a carb rebuild kit available that includes the new neoprene material, that is not affected by the gasohol fuel mix.
Agree with everyone to check the integrity of the fuel delivery system -- including proper venting of the cap -- easy enough to test the cap by leaving it off or loose, while putting the motor under a load -- clean out the glass bowl and assure that fuel flows profusely out of tank, while bowl is off/disconnected (use fuel shut-off valve, at top of glass bowl, to control the flow) -- next, might be a good time to rebuild carb with new needle seat and gasket kit -- simple task, hand tools are all that are needed -- shoot disassembled parts down with a couple of cans of carb cleaner, and use compressed air to blow out all air/vent and fuel passages prior to reassembly -- make sure to set float level to correct height -- also agree that ignition should be shot-gunned with new parts, if current parts are old -- not too expensive, and well worth the reliability gained -- new plugs, wires, rotor, cap, points and condenser. CarQuest sells some (all?) of these ignition items -- was recently rejuvanating a friend's Case and IH tractor motors -- believe he said that CarQuest had all of the ignition parts -- seemed to be good quality when I was installing -- tractors fired right off after replacement -- also, assure that the timing is correct, and the distributor is not loose (by some chance) -- BTW, the distributors are standard Delco 4-cylinder distributors, so parts are still available -- recently had one rebuilt by a shop in Charlotte, NC -- came back nice and clean, with all of the weights and plates movable, once again.
intothegoodnight