9 hours ago, Patcon said:

Who'd a thunk it!!

Yeah, I don't remember where I first learned that, but it's a thing, Ozone is unstable and breaks down quickly in our level of the atmosphere, but it's definitely a thing!

So I would surmise those vent holes are to prevent any pressure differential between inside and out side of the starter motor from causing a problem. Whether that pressure differential is from ozone or simply from just heating up the air space inside the starter, but you want to let it breathe.

I thought it was for the hairspray. You know...brushes and all that a starter needs.