Finally fixed about month ago, a 1970 IH cub. The short story, I replaced the carburetor, condenser, new points, valve adjustments, tune up kit, fuel lever. The shop adjusted the carburetor, service, new sediment bowl with a cleaned out gas tank. Old tractors are hard to kill, but when they don't work it is not cheap.

I have almost no experience with carburetors to get them to run close to perfect.