Max, I like your thinking we might be closer to an answer, as you say they are not over revving but revving way to high if you are just running over a lawn and you see and hear it all the time with these power torques, revving their guts out and for no reason. What I am looking at on the cam is the long flat section that gives a complete dead spot in the throttle control. And yes we have tried new springs and they made zero difference. I agree the governor tube to the diaphragm should be able to be blocked off and the carby used as a complete manual one is what we are aiming for. I haven't come across them running slow on full throttle but I can see how it is possible. There has to be a simple fix so everyone can follow. I will discuss my cam alteration with Bumps and see what he thinks, can't be any worse
