A starter motor is a device that helps start an engine by providing initial rotational force. It does this by engaging with a flywheel to bring the engine up to a certain speed. Starter motors are typically electric, but some engines use a hydraulic starter motor.

Starter motors are essential for starting most internal combustion engines. They are typically used in conjunction with a battery, which provides the power needed to turn the motor. The starter motor itself is usually turned by an electric motor, but some engines use a manual crank.

Once the engine is running, the starter motor is disengaged and the engine continues to run on its own. Starter motors can be found in cars, trucks, boats, and other vehicles that use internal combustion engines.