Hey People New here I have acquired a M F 204 industrial tractor got a few problems I can not get it too quit back popping thru carb have replaced .plugs ,wires, dist cap, rotor points @ cond and rebuilt the carb ,checked timing , ok removed the # 4 wire from the dist cap while running got good spark will jump an 1"..it quit popping until I plug the wire back in what's up with that any ideas will be greatly appreciated # 2 have no brakes they are internal can they b replaced thru the left round access cover on the diff...?..? THANK YOU,,!..! ohh the engine is a Z-134 continental gas