What parameter does a marine engine governor primarily regulate?

• A. Oil temperature.
• B. Engine speed.
• C. Electrical frequency.
• D. Exhaust pressure.

Answer: (B)

A marine engine governor is a speed control device. Its primary job is to keep the engine running at a specified revolutions-per-minute by automatically adjusting fuel delivery based on measured speed. If the load changes and the engine tends to slow, the governor increases fuel to restore speed. If it tends to speed up, it reduces fuel to hold the speed steady. This focus on maintaining a constant engine speed is why it’s the best answer. Oil temperature and exhaust pressure are influenced by operating conditions and cooling, but they aren’t what the governor directly controls. Electrical frequency can be affected indirectly because it depends on engine speed when driving a generator, but the governor’s direct parameter is engine speed, not frequency.