730 pony motor

Ok, someone tell me if I'm correct on this. When you pull lever to crank engine over and the teeth engage the flywheel, the only place that for slippage is at the clutch, correct? The overrunning clutch will not cause an issue, correct? The reason I ask is that many times when I engage the starter drive gear all I get is a buzzing sound with no turning of flywheel. So the process is to kill engine let it almost die and flip switch back on and if I'm lucky when motor comes back up to speed, pull decompression lever, then cranking lever, and it spins flywheel, release decompression lever, and it starts.

It kind of sounds like the teeth just arent meshing between pony and flywheel. Make sure you pull back the engagement handle slowly. I've seen people slam them to engage them. If you do it quickly on my 720d it doesnt always mesh with the flywheel and will cause a grinding noise. If i engage it slowly it always works. If your sure it is actually engaging the flywheel your pony clutch is slipping. You may be able to take clutch cover off pony and I believe theres 3 bolts in there to tighten equally. You may or may not be able to get enough depending on how wore out the clutch is. Someone correct me if im wrong.

The gear on pony motor is engaging the flywheel. I am trying to make sure the over running clutch could not be an issue or something else could result in the problems I'm having. Hopefully, I can get it squared away without having to overhaul the clutch and transmission.

The diesel will turn over easier if youre main clutch is disengaged. If your not using the hydraulics or pto you can al so disengage those before you start the tractor and it will be less for the pony to crank over. Hopefully you can just tighten the pony clutch and that will be enough.

I remember having trouble with a few of the overrunning clutches in those. Don't remember too much of the details though. I think I was able to get enough of it apart while still on the tractor.
You should be able to see if the shaft still turns in the outer housing as you crank it with the cover off. This would show the clutch disk to be ok. Or if the shaft does not turn then I'd adjust the clutch.

Sure sounds like the over run clutch to me-

Have you always been faithfully using the de-compressor?
The de-compressor reduces the shock loading and wear on the starting engine drive train.
I get a lot of blank and confused looked when telling people that. That usually answer with "Umm, well, duhhhhh it usually starts without using it.

Sounds like the over ride clutch. There are three rollers in there and a star drive wheel. The rollers develop flat spots and the star wheel develop grooves so the rollers can"t roll into the right position to work properly. Might be difficult to find good used parts as most of them suffer from the same wear problems.

I agree with Hillbilly2. Been there & done that with my 70D.

The 2 cylinder Deeres almost always stop with the crank in one of two positions. Either with the #1 throw up or with it down. For that reason the ring gear and pinion both wear where they always meet each other on these same few teeth. The leading edge of the teeth of both the pinion and the ring gear have likely lost their bevel & when meeting squarely tooth to toooth instead of tooth to valley and you bump the clutch.... it can't do anything but GRIND.

Some 30 years ago I found if I made the teeth "match up" before I started the cranking engine it did not grind. I did this by trying to engage the pinion with the diesel flywheel by fully pulling the lever back. Sometimes it simply would not go all the way back. (My 70 has a foot operated starter switch for the cranking engine.) Anyway they would slide right together with this tension on them when I gave a light bump on the cranking engine starter. I then let everything completely stop and then go put everything in the disengaged position before I would start the little engine.

I did this for nearly a year before I replaced the ring, the pinion and the brake. I realize I probably would not have this grinding problem today just because of the condition of my parts but it is with this little effort to this day I aim to keep 'em in this condition and have never had 'em grind since.

I've not worked on a 730 but I assume it the same as the 70D. There is a brake lining behind that starter pinion that is supposed to keep it from free wheeling up to speed when in the disengaged position. MAYBE just linkage adjustments and that brake could solve the problem but likely NOT. Out of adjustment & a worn out brake is what usually destroys the teeth to begin with which just makes a bad situtation worse.

Have heard of guys driving the ring gear off the flywheel then rolling it 90° so it presents new teeth to the starter but I have no experience with that.

Sorry it's long but maybe that helps?

Later.

Perhaps a little more detail is in order.
1. Flywheel cover is off, the buzzing is not related to engagement of the flywheel drive gear to the flywheel gear as they smoothly engage most of the time. The flywheel gear appears to be in very good shape, and the drive gear doesn't appear to be excessively worn either. When the two gears don't mesh it makes a very distinct grinding sound, opposed to the buzzing sound I hear when I engage the pinion gear to the flywheel and the flywheel doesn't spin over. They are two different sounds.
2. As for the decompression lever, yes I always decompress engine before I attempt to engage the pinion to the flywheel. I also decompress the engine when I shut the main engine off to avoid rocking of the flywheel due to the compression. It is the OEM flywheel and it is tight and I don't want to mess it or the crank splines up. Had that happen back in the 1980's flywheel became loose and had to cut tin cans use the slivers of the tin can, drive wedges to open flywheel up, and slide the slivers in between the splines on one to get the flywheel tight, the crank splines were worn pretty bad.
3. As for the Clutch brake perhaps it is worn. I did replace the pinion disengagement spring and that did help slow the pinion down considerably and it will completely stop pinion sometimes. However, simply stopping the pinion doesn't solve the problem of the slippage issue. What does seem to help is either killing the pony motor or almost letting it die then turn switch back on. That seems to help which made me question the overrunning clutch as a potential problem.

PS: I don't mind long winded messages. They can be very insightful at times.

Now that makes me jump ships! I'm on the overrunning clutch mechanism being "slippery" in a backward sort a way ship now! Have heard those grind, screech and make some nasty noises when slipping. Sure hope it never locks up during a start taking the cranking engine or transmission for short but REAL high speed ride!