460 PTO doesn't shut off proper

My 460 PTO is generally always on. If I push down on the lever it does shut off but seems out of adjustment. I don't have a manual for this so not sure what to do? Is something worn out or do I just need to adjust something to get it to stay in the "off" position better?

If it has a small oval cover on the top of the unit with a screw holding it in place, the following will make sense. it could have a different PTO so look for the
small 1.5X 2.5 sized dome like cover.

Make very sure there is no lost motion in the hand lever pivot and rod mechanism. Be certain the hand lever moves the PTO lever from the middle both ways.
Adjust it like this, after there is no play in links.
Move the lever exactly half way between the locked on position and locked off position (little flipper catch on lever.
Take off the little dome metal cover from the adjust screws.
Loosen the jamb nut, and tighten the front (away from you) screw until it is just a bit tighter than the point at which it begins to feel tighter as it is screwed in
(maybe a eighth turn) then back it off until the PTO shaft will turn with least drag (about 3/4 turn out) and tighten the lock nut while holding the adjuster.
Do the same for the closer adjuster.
If the screws go into the jamb nuts and get flush with the top surface of the nut, the bands are probably worn out, and may be operational for a while, but plan on a
rebuild.
Now (tractor off) push the the lever down toward the brake footplate. As it goes down, it should get harder to push when it is about 4" (or so) away from fully OFF.
and be noticeably harder to push for the last inch, but not real hard. (this is the brake band tightening on the drum in the PTO unit.
Then pull it up and do the same feel.
The ON position should feel the same way.
The shaft should turn pretty free when the lever is half way, and not at all when in either ON, or OFF. (tractor shut off)
If it slips now, it needs a rebuild. JimN

Thanks for that info! I don't see the dome cover though so I think mine might be different. Mine is a late production (1963, one of the last 1000 made). What I didn't notice before is there is a notch to hold it down in the "off" position, which was caked up with dirt. After cleaning that out... it stays put... so operator error. It's a new to me machine. I'm surprised that any position out of that notch is engaged though, so I'll still go through the adjustment settings when I get a chance to make sure we're in good shape.

The notch you refer to is to apply an internal brake. When you come off that notch , it would be pretty normal for the shaft to turn but it should not pull a load until you pull lever back and feel a definite over center click, snap, what ever. Then the lever is to remain free and no attempt to lock it in the engaged position. Just mention this because it is not unusual to see operators adjust the linkage so they can hook that pawl behind quadrant when in engaged positon. That will wear out the internal over center mechanism.