In my humble opinion the Massey engineering group made a terrible mistake with the placement of the return spring for the throttle cross shaft. They located it on the hand throttle rod to the cross shaft. The trouble with that is when you step on the foot throttle it also advances the hand throttle. Releasing the foot throttle the hand throttle then holds the engine rpm up. So after over thinking the problem for a day, it suddenly dawned on me to move the spring off the hand throttle rod. Simple relocating the spring holder to a 3" x 1/4 " bolt drilled in to the top flange support for the gear shift was the answer. Now the foot throttle and the hand throttle operate completely independent of each other. Other of the tractors in that series may have the same configuration. So the question, was it an over site by the engineering group ??