Starter Issues

[bwthor]

Starter on my old 706 gas tractor has been intermittently not engaging properly. I bought a cheap starter online last year, installed it and it would only spin, would never engage. Just figured I got a junky aftermarket starter, so sent it back.

Last week I went to the dealer and bought a starter from them. Installed it and I have the exact same issues, starter spins but will not engage. The starter I removed I believe is the one that came with the tractor when it was brand new. Anyone know off hand if the wiring was changed in the newer starters. I haven't had a chance to go out to where the tractor is to troubleshoot and figure out if I can maybe just move wires to a different lug to fix, or if I need to rig up some other type of relay. I'm pretty sure I can figure it out on my own, but always like to hear what others have to say, may save me some time when I go out there.

Thank you in advance, as always, your answers are much appreciated!

 

[rustred]

check the solenoid wiring. it has to pull the drive in to engage with the ring gear. bench test it first. u need to jump to the S terminal on
solenoid from the main power terminal once you have booster cables hooked to it. the solenoid has a pull in winding and a hold in winding.

 

[teddy52food]

How is the ring gear?

 

[used red MN]

Did you pay $400 for it? I am not asking that question
because I am nosey, it is because that is the price they
show for a rebuilt starter on the IH online parts catalog
and what the dealer should price it at. If they sold you
something for less than it came from a ..short line..
vendor, I do not know if this is a proper term in this
case but I am going with it. In other words it was not
delivered to the dealer on a manufactures parts truck.
So bottom line is this starter in reality may be no better
than the cheap one you bought previously. There is no
change to the wiring original and replacement starters
both connect the same. If your wiring was connected
wrong the starter would try to engage immediately
when you turned the key on. Rustred has a good test
to perform, although the way those starters are
designed and operate the contacts that engage the
starter motor and the mechanism that slides the drive
out are mechanically connected and almost have to
operate simultaneously. This is if something is not
broke or out of place.
Describe your problem with a bit more detail. Is the
poor engagement just the motor spinning or is it a gear
grinding noise, those are two different problems we
need to know which it is. Gear grinding may indicate a
section of bad teeth on the flywheel. If this is not your
problem I would just take the starter back to the dealer
and exchange it. Chances are slim, but do you have
your original starter? If you do I would suggest you find
someone to rebuild it. After having that original starter
rebuilt will have a much better starter than any rebuilt
you will get over the counter.

 

[bwthor]

This post was edited by bwthor on 05/21/2023 at 10:58 am.

 

[bwthor]

Replying in order...

I agree, starter spinning means it is fully engaged so my initial thoughts about wiring being different were going the wrong direction.

Didn't look at the ring gear, but I'd assume there is wear. For years, at least 10 or so, when you hit the starter when the engine is hot, it only engages 1 in 5 times. Usually fine when it is cold. Teeth on the starter are beveled and worn.

Starter was a little over 350, so I believe (hope) it was better quality than a cheap online one. Starter just spins freely, with no engagement to the ring gear at all, no grinding or anything. I'm 99% sure the gear size has to be wrong, but again I didn't compare when I swapped them

This post was edited by bwthor on 05/21/2023 at 11:01 am.

 

[used red MN]

So is it grinding or just a relatively quiet electric motor
spinning sound. If grinding then the flywheel having an
area of ground down teeth is very likely.

 

[wore out]

In that era, IH did some updates on ring gear and starter drive tooth counts.

I'm NOT sure if the 706 gas tractors were involved in that and I don't have the Service Bulletin at hand.

If that's the case, and your tractor is in the affected range poor engagement or excessive ring gear wear could have occurred if the drive and ring gear were mismatched, and how is one supposed to know for sure what MAY have been changed on an old tractor?

 

[rustred]

as i said bench test it and watch to see if the drive is flying out. if so then its the drive that is shot. a starter is not that hard to
figure out so pay attention as to what u are directed then post back with you details. we can help, we give info but things sure go sideways
in a hurry. plus post pictures of the drive that tells the story also. sure saves typing stories also.

 

[BarnyardEngineering]

Just for reference the starter can't spin backwards because you wired it wrong. It's not a permanent magnet motor. Notice how you weren't fighting with your tools and the bolts sticking to it? A permanent magnet motor that powerful would have made installation a nightmare.

The motor can only spin one direction, the one it's wound for, because the motor is electromagnet pulling against electromagnet.

 

[bwthor]

No grinding at all on new starter, just spinning freely like it does when I bench tested it. Gear pops out all the way to the end of the shaft.

Old starter grinds when it doesn't engage, never spins freely like the new one does. I called the dealer, and they still have the original there, so I'm going to stop in and verify the gear size, and double check the length of the starter snout. Has to be a difference somewhere.

This post was edited by bwthor on 05/22/2023 at 06:06 am.

 

[teddy52food]

Grab that drive with a pliars & it should rotate the armature one way & freewheel the
other. If it freewheels both ways it is shot.

 

[rustred]

exactly, now we are getting going. and have a look at that drive and do the pliars test as teddy said. count the teeth on each drive also.

 

[bwthor]

OK...Mystery solved. It isn't real obvious till you start looking a little closer, but the starter on the 706 is slightly offset compared to the reman one I purchased. See pics here - https://photos.app.goo.gl/s7s6ynJb3q3CMBZc7

And after seeing the offset, I found this old thread with someone dealing with the same issues.
https://www.yesterdaystractors.com/cgi-bin/viewit.cgi?bd=farmall&th=698199

Thanks again for chiming in, and I hope this thread helps someone down the road.
[/img:82602c95ba]

 

[bwthor]

Sorry for the double posting, this can be deleted.

This post was edited by bwthor on 05/23/2023 at 01:37 pm.