wrote:
: That "whizz" sounds like a slipping sprag clutch (Bendix drive). Don't
: run into that very often at all on those drives. It was more common on
: the old small Continental starter drives, which ran in oil and after a
: little wear they would start to slip.

Well, I've done a bit more looking. Probably should have done this before I
posted. What I thought was missing teeth on the ring gear is more like worn ones. I
rolled it over today (didn't start it because I hadn't preheated). At least this
time, it sounds like the gear wasn't fully engaging. Between that and the worn teeth,
it seems like it can get shoved back out of the tooth when the load gets high (i.e.
compression stroke).

I'll try to take a closer look this weekend sometime. Plausible theories
include:

- Low voltage causing weak solenoid engagement... voltage will drop even more as the
load goes higher and the starter motor pulls more juice. Most likely theory at this
point, but haven't narrowed it down to battery, master/starter solenoid, or wiring
terminals.
- Slipping sprag clutch.
- Binding on sprag clutch causing partial engagement.
- Bent shaft/housing causing binding.

I've been pretty careful with the battery, although I did let it sit dead
overnight once (left master on). I'm sure that damaged it some, as lead-acid
batteries don't like that at all.... could just be weak. We *have* owned it for over
3 years now.

-Cory

--

************************************************** ***********************
* Cory Papenfuss *
* Electrical Engineering candidate Ph.D. graduate student *
* Virginia Polytechnic Institute and State University *
************************************************** ***********************