The old mini kinda burned up so I got an exact replacement for it. The old one was installed with no shims and worked great and because the new one was exactly like it I did the same. The first time I cranked the engine it spun it over fine. When I tried again it ground the gears and made a horrible noise. I tried it quickly a couple more times and got grinding. I went under the coach to check it out and the clearance appears to be about 3/8 inch, quite a bit according to instructions. I assume the pinion isn't being thrown far enough to fully engage the flywheel. If I understand it, the shims are for if it's too close or touching, you can shim it out to get the desired 1/8 inch clearance. but how do I get it closer when there are no shims to take out?

Do you still have the old starter? Compare to see if the new gear is moving fully outward to engage.

The shims are usually used to set the radial clearance between flywheel and starter pinion. With the teeth engaged there should be minimal gap between the teeth. If it is too tight the pinion may not engage fully.

Seems odd an identical new starter won't work. Good luck.

See you soon. Heading south on the 11th.

So should I put a shim into see if that's the problem? Are you telling me the shim is to move the pinion gear further to the outside edge of the flywheel? That maybe it can't engage because it's to close to the middle of the flywheel? That would make sense I suppose. The new starter and the old one appear identical. I didn't check the throw on the new one but I figured it would be the same.

yeah, the gear may be binding on the way in. The classic test is to engage the pinion manually, then use a paper clip for a feeler gauge between starter tooth and bottom of flywheel groove.

Mine never needed shims but GM tolerances varied a lot in the old days.

Been pretty busy lately but today I'm going to put in 1 shim to see if that helps. I have 2 but figure I'll try them one at a time. Need to get the old Barth up and running so I can take care of some other things like the brakes and the fridge.