Hello Sapper,
I had a problem with an overreving Chinese Powertorque and seeing it was a late model straight manifold engine, I figured it was not likely to be either of the inlet manifold o rings, so I decided to check the governor diaphragm and as I suspected, it wasn't seated right when I pulled the cap off. One side was folded into the body. Once positioned right and forming a proper seal around the perimeter before replacing the cap, problem was cured.