An internal combustion engine includes an engine block, an electric motor, a worm coupled to and rotated by the electric motor, a worm gear coupled to and configured to be rotated by the worm, a crankshaft configured to rotate about a crankshaft axis, a flywheel including a flywheel cup having flywheel protrusions, a clutch driven by the worm gear and configured to engage the one or more flywheel protrusions such that the crankshaft is rotated, and an energy storage device electrically coupled to the electric motor. The clutch is configured to disengage from the flywheel protrusions when the rotational speed of the crankshaft exceeds the rotational speed of the worm gear. When the electric motor is activated, the electric motor rotates the worm rotating the worm gear, which causes the clutch to engage the flywheel protrusions, transferring worm gear rotation to the flywheel and the crankshaft to rotate the engine for starting.
