Start drive gear shattered twice...why?

Hi - The starter drive on my 841 has blown up on me twice now (see attached pix). Here is some background info. I'd like to know if anybody has any clues as to why this is happening.

I've got to buy new parts and don't want this to occur again (this time was in the middle of spreading 8 tons of gravel...ouch!)

- A while back I burned out my 6v starter on my 12v system, so I replaced it with a rebuilt 12v starter from NAPA. I bought a new starter drive from this site. A month ago the drive failed (the gear shattered and scored the starter shaft).

- So I got a new starter from NAPA and a new drive from this site again (the drive says "Made in India"...hmmm.) That was a few weeks back. After 8 hours of operation (lots of starts) the drive locked up the tractor again. When I pulled the starter, the gear was stripped like the first time.

My questions: anybody know why this is happening? I can think of 3 possible problems: flywheel, starter, or drive. The drive may not be good quality (both failed drives were purchased from this site, made in India). The starters were rebuilds from NAPA. The flywheel...?? I can't think of why it would wait a long time before trashing the starter drive. But I did have the flywheel off a few months ago. It went back on ok, no apparent issues.

Any ideas anyone?

TISCO and Atlantic are sourcing some parts from the same supplier. I've seen 3 drives from Atlantic look just like that. You should be able to get warranty replacement on that drive.

Get a used drive from a tractor salvage yard.Your trouble started when you decided to put 12 volts on a 6 volt starter.The fools that told you the 6 volt starter would work fine on 12 volts lied.There have been bad reports on new starters from India.They can copy things but they cant get it right.As for the scored shaft I would put it in a lathe and clean it up.

Bingo.

Dean

(quoted from post at 12:27:39 10/22/13) Your trouble started when you decided to put 12 volts on a 6 volt starter.The fools that told you the 6 volt starter would work fine on 12 volts lied.There have been bad reports on new starters from India.They can copy things but they cant get it right.

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I think you misread my post. I said I replaced a 6v starter with a 12v rebuilt starter from NAPA, not India. I wasn't running 12v through a 6v starter. The starter DRIVE (from TISCO) was marked as "Made In India".

But, do you guys think the problem is most likely a couple of faulty starter drives, or could something else be causing this?

Thanks....

Coupe is such an inverterate hater of all things solid state or 12V that all he has to do is see the term 12V and he wets his pants.

looks like soft steel to me...

You started by saying you BURNT UP a 6 volt starter on 12 volts.

Go eat some squash.

I think you are mashing the starter button to hard.
Ron

(quoted from post at 21:53:14 10/22/13) You started by saying you BURNT UP a 6 volt starter on 12 volts.

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That's true, I said, "A while back I burned out my 6v starter on my 12v system, so I replaced it with a rebuilt 12v starter from NAPA."

That happened a couple of years ago, and then only after it ran fine for about 5 years on 12 volts. So no problem there.

I only mentioned that to indicate that I now have a 12 volt NAPA starter. The issue of this post isn't about the starter, it's about the starter drive.

"Your trouble started when you decided to put 12 volts on a 6 volt starter". Nope, in this case, all the broken starter drives were on a 12v starter with a 12v battery.

Sorry for the confusion, I probably could have written that more clearly. My fault.

So nobody here has indicated any reason why these starter drives have failed other than poor quality (I don't think I was mashing the starter button too hard ). So OK, I'll start my discussion with the supplier, see what they say.

Update: The folks from this site contacted the source for this part and they'll be sending out a new one under warranty. No comment on whether there are known problems with these (apparently the failed unit was from Atlantic). So we'll see if it holds up. I appreciate the good customer service.

Lost the gear on the starter drive on my 8N, ( had been in there around 5 years) bought another, lost the gear after about 10 starts.

Removed the spark plugs from engine,(so I wasn't fighting compression) tranny in neutral, pto lever engaged, had my son turn the pto shaft with a pipe wrench while I looked at the ring gear through the starter hole...had 2 places where it was missing teeth.

FWIW

Fred

When mine failed on my 640 I had to split the tractor to get one of the broken teeth that had wedged itself between the ring gear and bell housing. Spent 3 times as long trying to rock it out than what it took to split it and let the piece drop out.

(quoted from post at 22:58:31 10/25/13) When mine failed on my 640 I had to split the tractor to get one of the broken teeth that had wedged itself between the ring gear and bell housing. Spent 3 times as long trying to rock it out than what it took to split it and let the piece drop out.

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I couldn't wait for the warranty replacement to arrive (regular mail from Florida to California) so I found one in-state from a non-internet tractor place, and they shipped it to me in a day.

It's a CNH 87421556 (Prestolite?). Interesting, it's not made in India, like the two failed ones, but in the US (according to the box). Don't know if it'll hold up any better, but at least it's installed and functioning for the time being.

I checked the ring gear, no missing teeth (whew.)