14 starts to rotate due to the inertia of the orc 40 it does not rotate initially as fast as the shaft 14 and is thus moved axially to the right by the helical splines 42 as the shaft 14 turns relative to the orc 40 against the urgings of the anti drift spring 54 at the end of travel the orc 40 has moved towards the end of the shaft 14 to the engaged position as shown in fig4 where the pinion 48 is in use engaged with teeth of a ring gear fitted to a flywheel of the engine being started not shown the anti drift spring 54 is now compressed as the motor is switched on power is also supplied to the solenoid 34 causing the plunger 38 to move to the right axially with respect to the shaft pressing against the orc 40 helping the inertia movement and resisting pump out or disengagement of the pinion 48 from the ring gear thereby providing positive retention of the pinion 48 in the engaged position until the power to the starter is switched off once the power is switched off the solenoid 34 releases the plunger 38 allowing the orc 40 to return to the disengaged position assuming that the engine has started at this time then the pinion 48 which is engaged with the ring gear will be rotating faster than the motor shaft because of the orc 40 the orc can now move axially under the influence of the anti drift spring 54 by rotating about the shaft 14 on the helical splines 42 if the engine has not started once the starter motor has stopped rotating the pinion 48 will slide freely out of engagement with the ring gear under the influence of the.