1,147,193. Engine turning gear. C.A.V. Ltd. Oct. 5, 1966 [Oct. 22, 1965], No. 44764/65. Heading F1K. A starting mechanism for an internal combustion engine comprises an electric motor, a shaft 2 arranged to be driven by the armature 1 of the motor, an axially movable pinion 4 operatively connected to the shaft, a device 8 for moving the pinion axially to an operative position in which it is engaged with the toothed wheel 5 of an engine and a one way clutch 40 disposed intermediate the shaft and the armature of the motor, the one way clutch being located within the armature. The arrangement is such that in the event of the pinion being maintained in its operative position when the engine has started the clutch will act to prevent the armature of the motor being driven by the engine. The clutch may be of the roller type or of the ratchet type or a multi-plate friction clutch having means to allow the plates to separate when the shaft tends to drive the motor.