955 12A 24V Starter

My starter stopped working. It spins, but the starter drive is not engaging with the ring gear. This is a factory Delco 24V inertia drive starter and SN 12A6341. I have good batteries and they're fully charged. It suddenly stopped working right.

I pull started the tractor thinking that would kick out the drive gear if it was stuck, but that didn't do anything.

Starter was rebuilt about 5 years ago by a reputable shop.

I will pull the starter in a few days, but I wonder what the problem could be before I do.

Hi,

most likely the inertia pinion thread is dry and so sticks back in the disengaged position. Some loose juice should see it work again.

The pinion lives in the flywheel housing and so is subject to clutch dust and moisture.

Maybe dismantle and clean out the starter itself, check the brushes and polish the commutator, and lube the armature bearings for a chance at some trouble free run time and starts.

Cheers,

Eddie B.

Thanks edb! It's a wet clutch on this one, but I may try to get an inspection cover off and spray it down...maybe if I remove the plate where the pony normally mounts.

your reply makes sense though.

OK, I got it off today and obviously the drive is not dry due to the wet clutch.

Bench testing with jumper cables shows the drive spinning out about halfway instead of to the end?

I load tested the batteries with the cables off and they tested good. Then I put the cables on and tested voltage at the magnetic switch and it shows 24.8V.

I checked the drive gear and it looks good except that it looks like it may be missing or broke some of the back side gear off but it looks factory,maybe a quarter inch...or did the shop cut out a section? Not the front side where it engages.

Flywheel teeth look good.

I don't see any seal to keep oil out of the motor like a Delco 42 on my other equipment? Could that be the problem?

i"ve had it rebuilt twice in 10 years, same shop.

The drive is located on the shaft with woodruf keys and a set screw holds it in position. The set screw has been known to get loose and allow the drive to slip position. I'd recommend you ditch the 40MT with the obsolete clutch type drive a go with a 42MT conversion.

Thanks OM.

Looking at the drive gear again, I can tell that it's made like that so nothing wrong there.

I think I found the problem. I sprayed down the drive assembly with brake cleaner and it started working right. Checking further, I can smell 90 weight oil in the wet clutch housing so somebody grabbed the wrong bucket and added the wrong oil which is making the starter drive clutch slip. I'll change the oil and go back with this starter for now and round up the 42 conversion parts as I have a couple of them in storage.