720 pony clutch

Good morning!

Well, I took a break from tinkering with my pony motor's clutch last year and just made due with pulling the tractor to get it started. I've got the tractor back into the shop and have been messing with it off and on for almost a month now. I've pretty well exhausted all the things I can think of for fixing it and need a fresh set of eyes. Here is what's happening. When adjusted according to specs (operating linkage and clutch adjusting screws)the pony clutch will not hold enough to start the big motor. I can get enough friction on the clutch to turn the engine over with the decompression lever engaged but as soon as I let the lever out the pony won't turn the big engine over and all I get is a buzzing noise in the clutch.

Here is what I have done/tried to remedy this. I have tried several different adjustments on the clutch adusting screws (to extremes on both ends:loosening and tightening). I have replaced the clutch disc itself, the bearing, dressed up the clutch plate and flywheel for kicks. I have adjusted the the linkage as well in all directions with no response. One thing to keep in mind is that this clutch works opposite to what you would think of for a clutch. Instead of using the throwout bearing to disengage the clutch, the bearing is used to push on the clutch fingers and apply pressure to the plate. Makes it kind of confusing at times. I appreciate any input that ya'll can give me.

I have this feeling that it is something that I am just simply overlooking because of having spent so much time trying things. I've had the clutch and transmisson completely apart (several times) and fixed/or replaced anything that could be replaced (except linkage arms and the clutch fork).

Thank you so much for your help. Here is a pic of what the clutch and linkage look like. God bless.

--old fashioned farmer

Check the link for the parts book and go to page 309 for a picture of the clutch.
720 clutch pic

Doesn't that starter drive have an over running clutch built in ? it could be slipping. Been years since I had one apart. I seem to remember them having rollers that wear grooves in there that may be able to be machined out.

Howdy Mike,

I had that apart too and found 3 of the 4 rollers to be in pieces so I replaced them and the springs. Didn"t see any grooves worn in there though. Thanks. God bless.

--old fashioned farmer

If the rollers don't have a clean fresh "detent" to sit in. They will slip/spin/grind.
F.I.T. is an expert with these clutches.

After looking at the pdf, I like to NEVER found the starter section, It looks as if the pony motor does not have an over-running clutch on the starter drive. I would look for stripped slines on the clutch disc of the pony motor and or the shafts listed as 2A or 2B which are the starter drive if I got those number right.

Kent

Howdy,

I spoke incorrectly on the overrunning clutch. I didn't have to replace any of the rollers. They were all fine. It was the caps that the springs sit in that I replaced. Sorry bout that. God bless.

--old fashioned farmer