I have a 51 farmall h that just up and quit running about 5 years ago. I have changed the condenser, put a new fuel system on it, plugs, wires, cap, rotor, all new ignition system, carb kit, and have cleaned the carb numerous times. I have fire at all the plugs. When you crank it over it will not start. To get it to even fire you have to pull the air hose off, choke it for a few cranks, let the excess fuel run out of the carb, crank it again unchoked then it will fire but you have to hold it at 3/4 choke to keep it running but it smokes and runs something terrible. something else that is odd is that when it is running there is smoke coming out the governer tube, but only when the tractor is running. I have good vacuum going into the carb when cranking. Any ideas would help please.