Which occurs when an engine is already in a self-sustaining state?

• A. Engine Requires Starter to Accelerate
• B. Engine Cannot Accelerate
• C. Engine Could Accelerate Without Starter Motor
• D. Engine Stalls

Answer: (C)

A self-sustaining engine continues to run and speed up on its own because the combustion process provides enough energy to maintain motion without external help. Once ignition has occurred and the engine reaches a speed where the fuel-air mix, compression, and flame propagation keep firing reliably, the starter motor is no longer needed. That’s why the engine could accelerate without the starter motor. If the engine still required the starter to accelerate, it wouldn’t be in a self-sustaining state; if it cannot accelerate on its own, it isn’t self-sustaining; and if it stalls, it’s not maintaining operation.