JD 720 pto clutch adjustment

I was using a bush hog on my 720D for the first since I got it running again after sitting 20 years. In low grass it works good , but as soon as get into heavy tall grass, the pto clutch slips and the pto stops working. I changed the oil and put new 10wt oil and tried adjusting the foot lever thinking that it was not getting engaged completely, but without success. I then openned the adjustment window and turned in the screw all the way as the manual said, but I could not figure out how get the adjusting cam to move to a different notch.

Is there some special thing o way I need to do to get that adjustment cam to move to a new notch to tighten up the clutch? I really don't want to tear that whole clutch apart if all it needs is an adjustment.

Yes, you turn the screw INWARD, releasing the slotted piece, then turn the slotted piece with a screwdriver.

Turn screw back OUTWARD when done.

"[b:654c4848f0][i:654c4848f0]Is there some special thing o way I need to do to get that adjustment cam to move to a new notch to tighten up the clutch?[/i:654c4848f0][/b:654c4848f0]"

Agree with [b:654c4848f0]Bob[/b:654c4848f0] on using a screwdriver.

Take a look at the information below on adjusting the clutch.

The screw must be visible before proceeding with the adjustment.



Engage the clutch. Working through the small opening, use a piece of wire .090-incb in diameter to measure clearance between clutch brake plate facing and flange of cam disk.

On a properly adjusted clutch this clearance is .090-inch minimum. [i:654c4848f0]NOTE: 3/32-inch welding rod gauge is satisfactory for minimum clearance.[/i:654c4848f0]



Working through the large opening, turn the adjusting screw cam locking screw in until its head clears the slot in the adjusting cam. Now turn the adjusting cam in a counter-clockwise direction (viewed from the rear) [b:654c4848f0]UP[/b:654c4848f0] to tighten the clutch moving the adjusting cam only one notch at a time while checking clearance through the small hole. Turning the cam counter-clockwise [b:654c4848f0]UP[/b:654c4848f0], which [b:654c4848f0]tightens[/b:654c4848f0] the clutch, will [b:654c4848f0]increase[/b:654c4848f0] the clearance. Turning the cam clockwise, which [b:654c4848f0]loosens[/b:654c4848f0] the clutch, will [b:654c4848f0]decrease[/b:654c4848f0] the clearance.

After the .090-inch clearance has been obtained, rotate the clutch and check clearance in two or three different positions to make sure that adjustments satisfactory in all positions.

When the adjustment is completed, turn the locking screw outward, into one of the notches of the adjusting cam. Replace the plugs.

Hope this helps.

When you say use a screwdriver to turn the slotted piece, I did that and it will not move. I turned the screw inward to the maximun until it won't go any more. Then I held the pto shaft with my hand and tried pusing on the slot with a screwdriver , but it just won't move.

It's been awhile and mine's an old 70, but I think the trick is to have the pto engaged. If it isn't snaped 'IN', the pto brake is engaged and things are pretty much locked up. To turn the shaft to get the screw in view you have to have the pto engaged at the rear, but not engaged at the "front" where the engaged to engine/not engaged to engine lever is. If you need to keep things from turning while you work on it, the pto clutch at the rear has to be engaged, as well as the lever at the front. I guess it's a good thing, but I could live without the pto brake entirely. I'm content to rest while everything naturally comes to a stop.