I normally work on the old Ford tractors, but I purchased this tractor a while ago and am having some difficulty getting it running properly. I can get it to start and idle fine, but I can only get it to rev up by working the throttle very slowly, if I go up normally it hesitates and spits terribly. I have done all of the regularly suggested checks, 2 new sets of points and condenser, checked timing and advance, checked distributor shaft for wobble, checked for vacuum leaks around manifold and carb flanges, checked spark and plugs, checked fuel flow out of carb., pulled and cleaned the carb. numerous times, numerous adjustment to main fuel jet. This tractor has a MS carb. on it with the main jet coming in at an angle from the bottom. Does anyone have any comments on the rebuilt carbs. from this site or the new Zenith carbs. also from this site. One of the fellows on the Massey site recommended that going to electronic ignition would likely solve my problem, any thoughts.