M1009 Runaway run-on starter

[GreggVA]

Issue: My starter continued to run after the truck was turned off and think I lost a bit of magic smoke.

The truck:

1985 M1009 with 27MT starter
Doghead relay mod
ST85 GP relay

My truck had been turning over very slowly and the batteries were fine so decided that the starter needed to be rebuilt. I took it to a shop to get it tested and they ended up rebuilding it instead so got it home and installed it. Nose cone stamped no shim so none were used, back bracket is in use, followed TM and torqued to 33 ft

I just finished installing and started for the first time. Very quick to start up and initially did not think there was any issue. After about 30 seconds, I started hearing a whine that I thought was bearing noise from an alternator. When the fast idle kicked down it was apparent that the noise was from the starter area and some smoke started rising from the firewall area. I quickly shut the engine off but the starter was still going. Not turning over the engine but just spinning and sounded slower. I pulled cables off batteries - think I got the rear to front battery cable first and then the other front cable which stopped the starter.

So does this sound like a bad relay in the doghead mod, solenoid main post and S post wires touching, bad solenoid, other? Do you think I will have to rebuild the starter again?

I briefly touched the battery lead back to the battery and the starter started a slow whine again. Any ideas on testing or where to go from here?

Thanks!

 

[Warthog]

Sounds like you need a shim on the starter. Just because it says NO Shim doesn't mean it doesn't need one. DH just covered this same issue with another Cucv today.

 

[doghead]

Read this.

http://www.steelsoldiers.com/showth...y-mod-rebuilt-gear-reduction-starter-run-away

 

[GreggVA]

Sounds like you need a shim on the starter. Just because it says NO Shim doesn't mean it doesn't need one. DH just covered this same issue with another Cucv today.

Appreciate your input but I guess there are differing views here http://www.steelsoldiers.com/showthread.php?116290-Starter-Rebuild

I know it's all worth what I paid for it too and I was motivated by laziness in the decrease in work I would do laying in the mud.

If I didn't have the issue before and I used the same starter, why would there be an issue now? New pinion gear and decreased clearance?

Just to be clear, key was in off position, engine was not turning over but starter was spinning.

 

[GreggVA]

Read this.

http://www.steelsoldiers.com/showth...y-mod-rebuilt-gear-reduction-starter-run-away

Doghead - yes great post and explanation. Only thing that I think was different in my situation is that I had my old 27MT rebuilt.

 

[doghead]

Just to be clear, key was in off position, engine was not turning over but starter was spinning.

That sounds like a solenoid failure. The large contactor must have stuck for some reason.

 

[Barrman]

I had the exact same thing happen to a rebuilt 27MT. It had a new solenoid too. It wasn't a Delco though and it stuck on. Just like with the lift pumps. If it isn't a Delco or US made, it probably isn't worth putting on your truck.

 

[Hasdrubal]

The original 24 volt starters have silver alloy contacts in the solenoid to prevent them from welding together when closed. Most of the aftermarket stuff is built too cheaply to include these special contacts, and therefore are prone to the contacts welding together when you start your engine, causing the starter to not shut off and burning itself up.


I got my solenoid from texasindustrialelectric.

 

[Skinny]

That sounds like a solenoid failure. The large contactor must have stuck for some reason.

My vote