D68U info needed

It has an oil clutch, but the clutch will not stay engaged, have to keep my hand on it to keep it pulling, the lever comes all the way back, but does not lock in. It started doing this after about 3 hours running it. Is there an adjustment on it, and if so can someone post instructions for it. Also need brake adjustment instructions, hopefully not from the back, or that big old winch will have to come off. Lastly, at idle the rpms go up and down, then when running full throttle when I release the clutch it sometimes goes up and down several times before settling down, back to full throttle. This is the tractor that had not been running for 10 to 15 years, and the rpm problem at full throttle started after I changed out the fuel filters, and it runs good otherwise. Thanks for any help. Dennis

Hi Denis,
here are scans for you to adjust by.
Hope this helps.
Cheers,
Eddie B.

Tighten clutch adjustment if your lever is pulling back against the edge of the seat before the tractor moves. If it's engaging farther forward, but won't snap in and hold, it's too tight and needs loosening until it will snap over center.

Clutch adjustment is pretty simple, clean floorboards etc and cover on clutch compartment so you don't get dirt in the clutch housing. Use clean tools inside.

With decompression lever pulled, you can rotate the flywheel until you see the lock tab and 3/8" nut (9/16 wrench) that holds it against the clutch adjusting ring.

Loosen the nut. Tap the locking tab to loosen it on the stud.

Rotate flywheel half a turn and loosen the second locking nut. Then you should be able to turn the adjusting ring a few inches clockwise if it needs tightening or counterclockwise if it needs loosening. Test the pull on the lever and adjust more as necessary. You want a snap in, but not so hard you'll be worn out at the end of a day from pulling it. Spec is about 55 pounds pull while stopped. It is supposed to ease up a bit when it's running. Retighten to 30 foot pounds

On the brakes, the adjustment is necessary if the pedal moves more than 3-4 inches without stopping the track. If you adjust too tight, (less than 3 inches) effectiveness seems to be lessened too. Seems to be a sweet spot in the middle there where they're most effective.

Covers to access the brake bands are underneath the seat accessable from the rear working beside the winch without taking it off. Tighten adjuster nut until you get the correct pedal travel, It is oriented with the long axis of the tractor, tilted a bit forward from vertical and in line with the brake band. It has a little spring loaded gizmo to stop it from moving on it's own. Then check the band support screws underneath the tractor. To adjust them, tighten the brake up with the foot pedal and then run the support screw up until it pushes the brake band tight against the drum. then back off 1 1/2 turns and lock the lock nut. This keeps the band from sagging and wearing against the drum while the brakes are released.

While you're under there, check the drain plugs on the steering clutch compartments which are near the band support screws and lock nuts. These are a pipe plug thread about 1" diameter. Bevel gear compartment drain plug is on center line of tractor, so don't get that one unless you want to change that oil!

While the adjuster covers are off, you can also adjust the steering clutches to 3" free travel at the top of the levers. Before you do this, make sure there is nothing keeping the levers from moving back to the full forward position against the rubber bumpers. Sticks and other debris can collect in there and prevent them from working right.

The clutch adjusting nut on each side is on a horizontal stud which protrudes from the center of the tractor and has a smaller lock nut which must be loosened before moving the large adjusting nut next to the clutch yoke.

Have you checked the oil in the injection pump housing? The way your's is behaving, it might help to have something thicker in there, but it calls for 30 wt like the main engine. Also check the oil in the pony pinion clutch compartment.

Thanks for the info. CC I cannot access the covers on the brakes from the rear, because of the big worm drive winch on the back of this thing, so may have to pull the seat tank. There are access panels cut in the underside of the fenders, but cannot see through them. I checked the oil in the pump, but did not change it, so I will try that.