New problem found, PTO
 

71 Cub K161S PTO won't disengage. The belt is very tight. Tried to get a pic of the front but, won't turn out without the grill removed. Any way the front of the PTO looks good nothing loose. Notice the clips in the grooves?

It looks like the Bronze PTO Wear Button is missing from the disengage lever/arm, it pushes in on the pto to over ride spring pressure and allow the clutch disc to slip.

As mentioned it looks like your wear button on the piece of steel the comes up in front of your PTO is pretty much shot. A new button and then readjusting the turnbuckle on the PTO release rod should get you fixed up. You can find the service manual for your cub in our Tractor Library. It shows how to get your PTO release adjusted.

It looks like the whole PTO has shifted forward on the crankshaft. Check out the holes for the set screws. They are forward of the holes in the pulley. What do others see? I am thinking that the set screws have not been set BEHIND the bearing, but have been tightened into the bearing race. They have come loose and the PTO has slid forward. This could keep the clutch from disengaging.

I agree that it does look like the PTO has slid forward. The cutouts in the wavy part is where you should access the set screws for the PTO. There should be TWO in each location, one on top of another in each hole. They are 1/8" hex (allen) wrench .

( the PTO button is shot--replace it)

Good eye on the PTO moving forward, I was only seeing the release lever. Time to pull the front grill off and do some repair work.

Now that you mention it, I see it too. So your saying to release the set screws and push it back into place? Since it is like that, is there anything that would have been damaged (PTO) if ran like that? It wasn't running when we got it and haven't gotten it to run yet. Waiting on another carb to rebuild.

How do you replace the button?
I thank you all for pointing out my problem.

After you remove all the setscrews (6 total, two in each hole) remove the PTO from the drive shaft. On the back will be three bolts ends with 2 nuts per bolt. One nut is called a "jam nut" and the other one is the nut. SEE NOTE BELOW BEFORE YOU DISASSEMBLE IT!!!!

Remove all nuts and the PTO will come apart. Then you can replace the button and put the PTO back together. You will need a special "ruler" (a metal gauge) that will let you set the correct tension on the springs inside the plates. The "ruler" comes with a rebuilt kit with the replacement clutch.
When you put it back together, make sure the PTO slides onto the crank up to the snap ring at the front of the PTO.

NOTE: Or you can count the threads stuicking out of the jam nut, take it apart and re-assemble it with the same number of threads showing. Not recommended, but you got to do what you got to do.

Hope this helps.

I believe the button Charlie-141 FE and DX3 was taking about is on the release lever, which is worn. The PTO seems to be fine except it is mounted forward of where it should be.

No that I re-read his post, I see that he was talking about the wear button. The PTO will have to be put back in place, set screws installed, then the wear button will probably pop out of the arm easily enough, plus there should be enough room since the PTO will now be moved back about an inch or so.