I have a 1950 M that is not running correctly. When I purchased the tractor it was running OK. I cleaned the sediment bowl and found that it was partially plugged coming from the tank. It ran fairly good after that and we were able to disk about 3/4 of an acre a couple times over. We than attempted to plow with it and the problems started. It would stutter and smoke and die when we attempted to make it "work". Upon inspection the spark plug wires were "used", the distributor cap was shot, points were ok. We replaced the spark plugs, wires, distributor cap, rotor, condenser. It also has a new battery with a good charge. The timing was also checked and seemed to be ok, and changing it didn't seem to change anything. We were told that it could be gas related. So we pulled the carb, cleaned it with electrolysis, used heavy duty carb dip to clean all needles and jets. Everything was put back together according to the book as far as I can tell and it still will not run correctly! Attempted to adjust it while it was idling and it seemed to run good. When it was put in gear and driven across the yard, it seemed to have a hard time pulling itself forward. Does anybody have any suggestions??? Also what is a good place to start with the needles as far as adjustment? Any help or suggestions would be very helpful!