first thing to do is determine which carb you have on your tractor.
I have a 1957 model TO-35 and it has a Marvel Schebler tsx 605 carb.
they also made TO-35's with zeinth carbs.
each will be adjusted differently.
if you have a ms carb your end result will be to have the tractor (warm engine) idle smooth at 400 rpm's.
My old tractor runs good and idles at 400 rpm's
search for carb adj information for your carb.
be sure the plugs, points and timing are new and adjusted properly before you start.
normally if the tractor runs better when choke if partially closed then carb is stopped up.
i have even taken the air cleaner off my old tractor and soaked it for a day or two in a 5 gal bucket of gas, then drained it out and let it air dry. you would not believe how much dirt was caked in that old air filter screen, washed it out until it ran clean.
I will continue to look for carb adjustment sheets for tsx 605 if that is the carb you have.
note to file: i installed a metal fuel filter between the fuel cut off valve and the carb. The old screen in the fuel cutoff and screen in the elbow at the carb just did not keep the fuel clean.