Ford 600 Choke on rubs good??

[nealtractor]

My Ford 600 only rubs smooth with the choke on, cant figure out what to adjust. New tractor to me, first tractor to me!

 

[Zebrafive]

With choke on you are making the fuel mixture richer. Sounds like something in the main jet circuit is plugged or parcially plugged, I would clean/rebuild the carb.