Abstract: A starter for an engine includes a housing. A starter motor in said housing includes a field apparatus including a tubular yoke being provided to form a part of the housing. An annular ventilation passage is provided in the starter defined along an inner periphery of the yoke and being hermetically sealed from an inside of the yoke. A first ventilation hole is defined proximate a bottom portion of the housing for interconnecting an inside of the passage to an outside of the housing. A second ventilation hole is defined proximate a top portion of the ventilation passage for interconnecting the inside of the passage to an inside of the starter motor.

Abstract: A starter for an engine, having a ring gear includes an output shaft for slidably holding a pinion gear engageable with the ring gear, a housing having an opening portion that enables the pinion gear to engage with the ring gear when the pinion gear advances, a cover having a shutter, a front wall and a side wall for sliding together with the pinion gear. The shutter opens the opening portion when the pinion gear advances and shuts the most part of the opening portion when the pinion gear retracts. The front wall is provided to cover at least half of a front portion, which faces to the ring gear, of the pinion gear. The side wall is extended from the front wall in a direction parallel to an axis of the output shaft to cover at least half of the gear tooth periphery in a circumferential direction of the pinion gear. When water carried by the rotating ring gear comes to the opening portion when the pinion gear rotates with the ring gear, most of such water is blocked by the gear tooth.

Abstract: In a small starter motor which has a substantially closed space therein, it is necessary to blow out brush dust particles therefrom. On a coil end surface or both coil end surfaces of an armature, a fan generating an air circulation is formed utilizing gaps formed between individual coil ends on the surface without adding any other parts. Also, a side wall is disposed next to the coil end surface in parallel thereto which closes an axial end of a yoke in which the armature is coaxially disposed. In the space formed between the side wall and the coil end surface, an air circulation is generated when the armature rotates. The side wall has an air inlet hole and the yoke has an air outlet hole. Air coming into the space from the air inlet hole is blown out from the air outlet hole by the circulation generated by the fan made on the coil end surface. The brush dust particles are blown out by the circulated air, and the coil ends are cooled off at the same time.