Starter sometimes not engaging question

[MattNC]

Hi All

Id like to tap into the huge amount of experience and knowledge here on an issue I’m working on. Starting this week a few times the starter has not engaged the first try. It just whirls or barely grinds then whirls. If I wait for it to spin down and try again it works fine.

Its happened when cold, when hot and after running for an hour, sometimes not for 10 starts in a row. Seems random. I searched the forums and checked quick test items.

Cold voltage was 12.6 and 12.9 on fairly new batteries. The alternator is charging within the specified range of voltage. When it does turn over the first try 90% of the time it turns over very strong and fires right up. The engine is old on this M998 (a 87 engine) but had been rebuilt pretty recently by a gov contractor who put stamps and labels on everything including the starter. They seemed to do good work. If it starts the first time I can restart it ten times in a row in quick succession with it picture perfect.

So so before I start tearing into it what would you look at first? Could it be a solenoid on the starter getting sticky? I’m not sure if that can be replaced by itself. I guess checking the gear teeth would be worthwhile if I get the access covers off. In the past the engineer in me just grabs a wrench and starts taking things apart but I’m trying to use my head and collective knowledge first this time!

Thanks!

 

[donquijote]

Having fixed this problem before. It's more than likely a bad bendix gear on the starter. Given that it whirls after engaging. Bendix or the solenoid is the issue.

I've rebuilt the starter before and replaced the bendix gears. If you got the cash I'd look on fleabay for a new rebuilt that costs around $330 from a guy here in LA. Unless you enjoy rebuilding parts.

Also, while you got the starter out. Upgrade the support bracket from the newer humvees. It's cheap and makes installing the starter much easier. The first gen was designed by someone not using their head.

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[snowtrac nome]

on the hmmwv its most likely a tooth worn on the flywheel, I did have a leacenaville starter on my lmtv do that and it had a bent fork on it. I have seen very few gm style drives fail they weren't like the old Chrysler gear reduction starters from the 70's. that said delco drives can fail to, once the starter is out the first thing I would do is bar the engine over and inspect the flywheel.

 

[MattNC]

Thanks guys! Donquijote would you mind sharing the sellers name via a post or PM? Thanks again

 

[donquijote]

Thanks guys! Donquijote would you mind sharing the sellers name via a post or PM? Thanks again

Seller is mtpdtsllc

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[donquijote]

For anyone else coming across this thread, here is a side by side pic of the old vs new support bracket for reference.

New bracket is the one in my hand. If you install and the starter bolt holes dont line up. Take a small torch heat the bracket at the hook part and give it a couple taps with a hammer after bolted down. Will bend it just enough to allow the starter to seat properly. Had that issue with a couple of them.

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[Wire Fox]

For anyone else coming across this thread, here is a side by side pic of the old vs new support bracket for reference.

New bracket is the one in my hand. If you install and the starter bolt holes dont line up. Take a small torch heat the bracket at the hook part and give it a couple taps with a hammer after bolted down. Will bend it just enough to allow the starter to seat properly. Had that issue with a couple of them.

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That newer bracket looks so nice...If I had a mind to touch anything on my starter, I'd just throw one of those in there on principle. That said, I've already bench-pressed a starter up into place while a friend tightened the bolts, and I really have no interest in removing the starter unless I have to again... If that moment comes, I'll order that bracket alongside whatever parts I need to repair it and greatly enjoy the improvement.

 

[MattNC]

This is great help guys! The only way for it to be any better is if you were there in the shop helping me!

 

[MattNC]

Thought I would bring this thread to a close with a final update. Pulled the starter, took it to a starter rebuild shop. $95 later it was done and was not the solenoid but the brushes were barely left, and a handful of wear parts were replaced and connections cleaned. I went to put it in with the new bracket (yes that makes it much easier) and called a neighbor to help for "ten minutes max." Famous last words! After bench pressing it 25 times and not getting it to line up we realized the shop had put the cover on rotated 90 degrees so the studs wouldn't line up right. 5 minutes and 90 degrees of rotation later it popped right in.
A trick I'd like to pass along, maybe already used by others. The challenge is lifting and rotating a starter into place while also keeping the shim on and aligned during the lift and not dropping the bolts and shim onto the floor or your face. I put the bolts through on the benchtop, the shim on top and covered the bottom of the bolts with painters tape to hold them in place during the lift. Once in position, my helper uncovered one at a time and hand started them into the holes. Once both were there we pulled out one at a time, applied loctite, and reinserted and torqued.

Matt

 

[TOBASH]

Thought I would bring this thread to a close with a final update. Pulled the starter, took it to a starter rebuild shop. $95 later it was done and was not the solenoid but the brushes were barely left

Matt

Brushes are a frequent starter and general motor issue. They cost pennies. Can't tell you how many motors I repaired with just opening up and replacing brushes.

 

[papakb]

A simple trick to keep the shin in place while your doing your gym workout is to tie it to the starter with some plumber's teflon tape. That'll hold it on place and it'll squash out of the way when the bolts are tightened up.