I did a little investigating on this machine, and after taking the throttle body(carburetor, if you will) off, I found another butterfly below it actually in the governor body. There is a little arm on the butterfly plate that is actuated by vacuum(or pressure), and it was almost broken off. I got some JB Weld and glued it back on. It was wobbling back and forth and getting out of it's little notch and then sticking so it wouldn't actuate the governor control. It runs great now. Thanks for inquiry, and I hope this helps.