YJ eating starter motors?

[hscrugby]

Got a buddy with an older YJ.
It's got a couple of quirks, (leaky rear main seal, and some other minor things) but the main one is it thinks starters are tasty.

You replace the starter, it will start fine 4-6 times.
Then on the 7th time, it just whines, like it's spinning, but won't turn over the engine.
You take it out, and the teeth look a little chewed, but not demolished or rounded off by any stretch. Looks more like the difference between "brand new" and lightly used.

I haven't seen this, I'm going to help him on Sunday, just figured I'd see if anyone here had any better ideas than mine.
Only thing I can think of is it isn't mounted all the way? but I didn't think the 6 cyl's needed shims (or could use shims?) like the 4cylinders do?
Can you over tighten the starter bolts?
He said he couldn't feel any play in the flywheel, but could that be a cause?
Any other ideas?


(And yes, I am using this as an excuse to procrastinate tearing into my jeep cause it seems easier)

 

[russ0943]

Not an expert at this but there should be a spec for the clearance between the bendix gear and the flywheel teeth. You might be able to check it with the inspection cover on the bellhousing off.

Other possible areas to look into. It may not be getting the juice it needs to kick the flywheel over and might just run into the teeth without having enough force to turn the flywheel and mesh. Check the resistance in your starter cables. Check voltage drop across solenoid. Ran into this problem with my boat and went through 3 starters. Tried shimming it and all. Finally it just started working with no shims. I would not recommend over tightening the starter bolts. I did this and it cracked the starter housing once. Had to hold the starter in my hand and bump it over to get the boat back to the dock!

 

[Ron]

flywheel teeth could be wore down and starter is only making contact with 1/2 gear teeth.

this is one of those deals where it could be numerous things but would think a quick visual would make it pretty apparent.

How is compression? If its real high may need a high torque starter.

And I neer use starters or other electrical stuff from AA or AZ...just bad experience

 

[hscrugby]

As an update since we got it over to my house today to work on,
It is DEFINITELY the flywheel.
Prolly 3/4 of the teeth are about 1/4-1/2 the size they SHOULD be.
Didn't actually get to replacing it, since we managed to do some other junk he needed first.
(and I'm lazy and couldn't borrow the real transmission jack)


Any helpful tips for dealing with the clutch? Other than if we want to reuse it, make sure to remove the bolts evenly?