340 PTO clutch

I am trying to adjust my 1959 340's PTO clutch. (It basically needs the linkage set so it turns all the time to get it to hold, if I set the linkage so it stops, it slips)
At any rate once I get it off, I cannot move the lever to engage or disengage it. Are they just hard to move, or could something be jammed? Any advice would be appreciated.

If there is any wear or lost motion in the linkage (at all) the adjustment will be off. (way off in some cases) (reprint from prior post of mine):
The linkage on well used PTOs on these become dysfunctional after years of use.
Two suggestions:
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. Peanut shaped on the top of PTO.
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 (brake)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 brakes. 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

That sounds like a totally different clutch. This is the stacked we clutch type. The adjustment after removing it from the tractor, is to rotate the spider until it moves .045 in when engaged.
I think my problem is just that I am underestimating the force it takes to move the lever when off the tractor.
I just was hoping for some confirmation before I put a pipe on it to get it to move.

Later production had a different PTO I was looking at the Parts List and didn't see the clutch type listed. Jim

It does require some force, even when mounted on the tractor with the extra leverage provided by the linkage and lever it takes quite a lot of force to get the lever lock engaged. Off the tractor you would need a pipe or some kind of extra leverage to disengage it.

That did the trick. 24" pipe wrench (almost pulled the board the vice is on off the bench) clicked it in and out.
I could not get it in the range of the specs. One click went from .030 to .048. It should be in the range of .035 - .045 so I left it at 0.48

That thing is a monster to re-install.

Thanks for the feedback.