If it revs too high, then the governor did not pull the throttle plate closed as the rpms increased.
You can get a full service manual in PDF at Kohler's web site. It covers a lot of the CV series and more.
I would look closely at the throttle linkage. The throttle plate normally is pulled wide open by a spring. The spring tension is set by how far you have pushed the hand throttle control, making it stronger to oppose the governor and keep rpms higher. When the engine starts, the governor starts pulling the opposite direction to the spring tension, and they balance out somewhere in the middle, not too high and not too low. When the load increases, the rpms drop, the governor weakens, and the spring increases the throttle plate opening to provide more power to meet the increased load. When the load goes down, the rpms increase, the governor gets stronger(with rpm increase) and pulls the throttle towards a more closed position.
It all is a tug-o-war between the throttle spring and the governor.
Your governor did not close the throttle with rpm increase. It is not working, has linkage problems, or needs to be adjusted.
Be careful if you start the engine again, as you can cause the engine to self-destruct if the rpms get too high.
tom
