GOVERNORS

The purpose of a governor is to keep the engine from destroying itself by running too fast. There is one hard-and-fast rule about them for homeowners: Leave them alone, The only exception is the governor spring on some designs. If you accidentally elongate the spring while removing the carburetor replace it.
Despite these restrictions, perhaps you would like to know how it works. The air vane governor, shown in l-26 and 26a, is the most common one.Its operation is quite simple: An air vane connected to the throttle shaft is positioned near the flywheel whose fins blow air and thus serve as the engine’s cooling fan. The faster the flywheel spins, the greater the air flow,which pushes on the vane, At very high flywheel speed, the air flow is sufficient to move the vane. The movement of the vane tends to pull the throttle shaft toward the closed position, stretching the spring which connects the lower part of the throttle shaft and a bracket. As the throttle is pushed slightly closed by the action of the vane, engine speed drops. Thespring coils pull together and the vane assumes its normal position.
The position of the spring on its bracket is adjustable if necessary, but leave it alone. The spring itself is a carefully calibrated part, so handle with care. Many engines employ a mechanical governor. This is a centrifugal device mounted on the crankshaft or its own little shaft. There are literally dozens of types of mechanical governors, but a typical one might be a component with counter weights that swing out at high speed and push a link, connected to the throttle linkage, toward the closed position.
The mechanical governor is usually an internal component and doesn’t get in the way of routine service. The only exception of note is the governor on the Lawn-Boy mower, which is under the flywheel and must belifted off the crankshaft before you have access to the points.