The starter (10) has a driver (15) which has a cylindrical outer surface (29) behind a single-track pinion (18) forming a sliding guide through an aperture (30) in the casing (11). The driver has a radial stop collar (46) fitted axially between the pinion and the outer cylindrical guide surface (29). A rear axial surface of the collar acts with a stop surface (62) on an external surface of the casing in order to set the rear rest position of the driver. The collar may extend radially outwards from the front end of the outer cylindrical guide surface of the driver.
