Well you learn something every day !

Yesterday we were going to drive to the beach....but when I turned the key, the starter motor just span round, and didn't turn the engine over. After several attempts, we went for a walk instead :(

So today I took out the starter motor and had a look at it.
The first obvious thing was gunge on the solenoid connector. So I 'hoped' that that was it, and cleaned it and put it all back. Nope, still just span round :(

I can now remove the starter motor in 5 minutes

So, out again, and onto the kitchen worktop to be stripped down.

The solenoid looked nice and clean and went in and out OK. I realised that the battery wouldn't be connected to the motor until the solenoid had pushed the gear onto the flywheel, so the solenoid must have been pushing the gear in.

Hmmmm, so the manual must have been right when it says "if the motor just spins the internal clutch is slipping and the unit needs replacement" !

So, I've degreased the shaft and roughened it, hoping the funny clutch thing that sits on it would now grip.

Back in the car, and for about 6x goes it didn't work. Then suddenly it worked, and has done every time I've tried it ?(

I think a new starter motor would be about $500 :(
A reconditioned one might be just as unreliable ?!

So I thought I'd try and find out how this funny clutch thing works.

And this is what I found:

A great description of the Sprag Clutch design.
http://www.formsprag.com/PDF/Principles.pdf

It allows the motor to turn the engine over, but when the engine fires and goes faster than the motor, it just slips. ie you can only drive it one way.

It's funny how mankind is reliant on a simple bit of design like that

The question now is.....can I make mine work reliably, or is it going to cost me ?

Steve

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I've tried it about 20 times so far and it's worked every time !

Went shopping today, and parked at the top of the car park
It's odd how you notice slopes when it matters.

Tom, it's a Subaru Legacy. Yes same car !
I read the Dog & Lemon when we got here, so avoided automatics, diesels (sorry) and turbos, as they appear to be the most costly and least reliable.

I can even show you the offending piece of machinery, as I took a picture of it yesterday, which is really handy as the guy I'm talking to about it wanted to know the number on it, and that saves me climbing into the car again

It's a pity I didn't take pics of the insides, as that's quite interesting.
Next time I strip it down

Steve