What is the role of a governor on a marine engine?

• A. To convert mechanical energy to electrical energy.
• B. To regulate engine speed by controlling fuel supply.
• C. To lubricate the engine.
• D. To provide emergency stopping via shutdown valve.

Answer: (B)

A governor on a marine engine is the device that keeps engine speed at a chosen level by adjusting how much fuel is fed to the engine. It constantly checks the actual speed and compares it to the desired setpoint. If load changes push the speed up or down, the governor moves a linkage or electronic actuator to change the fuel supply—reducing fuel if the speed gets high, or increasing fuel if the speed drops. This keeps the engine running smoothly at the intended RPM and helps prevent overspeed or sluggish response under different sea conditions.

The other options describe functions not performed by the governor alone: converting mechanical energy to electricity is the job of a generator, lubrication is handled by the lubrication system, and while some systems can cut fuel to stop the engine, stopping via a shutdown valve is a separate safety mechanism rather than the governor’s main role.