How do mechanical governor systems maintain constant engine speed?

Mechanical governor systems maintain constant engine speed by utilizing a combination of gears, flyweights, levers, and springs. This system operates on the principle of centrifugal force generated by the engine's rotational speed.

As the engine speed increases, the flyweights in the governor system move outward due to centrifugal force. This outward movement is linked to levers that interact with an adjustable spring mechanism. When the engine speed exceeds a preset level, the flyweights pivot to exert force against the spring, which then alters the throttle position to reduce fuel flow or airflow to the engine. Consequently, this adjustment brings the engine speed back to the desired level.

The effectiveness of this mechanical design lies in its simplicity and reliability, making it a common method in small engines to ensure consistent performance under varying load conditions. It does not rely on electronics or hydraulics, which is what distinguishes it from other more complex systems.