What happens to a mechanical governor's components when the engine speed decreases?

When the engine speed decreases, a mechanical governor operates to maintain a consistent speed by adjusting the throttle position. The flyweights within the governor system respond to a drop in engine speed by moving inward, which causes the sliding cup to move down. This downward movement adjusts the throttle plate to open slightly, allowing more air and fuel into the engine. The increase in the air-fuel mixture helps to boost engine speed back to the desired level.

This mechanism ensures that the engine can respond dynamically to changes in load and demand, keeping the engine operating at the optimal speed. The ability of the flyweights to adjust the throttle position is a fundamental aspect of how mechanical governors function, highlighting their role in maintaining engine performance.