It sounds like your govenor is operating as it should. The reason the throttle butterfly is almost closed at full power is because that's all the throttle the engine needs to maintain top governed speed with no load. If you watch the throttle while you engage the blades, you will see it open mometarily to encrease power to accelerate the blades, then drop back to almost closed again. When the engine is not running, it's not obvious how the govenor is supposed to work. Briefly, the operator control os connected to a spring that tends to pull the throttle on the carb open (faster). Opposing this is a link connecting the engine govenor to the throttle, that tends to close the throttle. The engine will accelerate until the force from the govenor equals the force from the spring. If you want more engine speed, all that is necessary is to increase the tension on the spring. Most Briggs engines have a star-head (similar to allen screw) bolt installed in the govenor/throttle assembly, the purpose of which is to physically limit the travel of the operator control. This can be safely removed, as the engine will still be goverened to it's maximum safe RPM (usually around 3800).
phil_saunders@bigfoot.com
Phil Saunders
June 2008