I found it so frustrating when my PTO was cutting out, I ran 2 wires from the PTO connector by the fan to a DVM. When I would be mowing, I had the meter turned on to watch the voltage at that point to see what it was when the clutch dropped out. I believe that was probably the only way I could have found the broken wire inside of the insulation jacket.

Next step?
 

Ok I have a wiring diagram and a test meter...what would the next step be, this is new to me!

Let me see if I can take a picture to describe it better. Like they say a picture is worth a 1000 words.

I'm willing to do the work, but really need guidance regarding wiring. I have a wiring diagram, but since the wires aren't laid out neatly like the diagram, in reality how do I go about this? What should I remove to get to the wiring, if anything beyond the sides and lifting the hood? Don't mean to be slow about this, it's just a little new for me. Thanks.

Sorry for the delay, BLASTED internet keeps dropping out and has been out for the last 3 days - #@#%&#*#$

I connected a DVM as shown below. However not shown in the pictures, use duct tape to hold the leads in place and also hold the meter in the spot show so I could see what the voltage to the clutch was when it dropped out. I needed to determine whether it was the clutch winding that was bad or the circuits in the tractor that was causing a problem. when I saw the clutch dropped out AND voltage was still applied at the point the meter was connected, it greatly narrowed the search to what the problem was and where it was located. In my case, the voltage was there when the clutch dropped out. While having the wife in the drivers seat with the PTO on, simple movement of the wiring AFTER the connector exposed a broken wire that I was able to repair.

Attachment 79235
Attachment 79236
Attachment 79237

Explain wiring on 1772
 

Here are some pics of my Cub's wiring. The safety shut-off is disengaged and has been for quite some time. Is it possible a wire was pinched when everything was put back together after resolving the gas line issue? Note the white wire near the rear lights wire - what is that for? The colors don't correspond to the wiring diagram from the manual, so it's a bit confusing.

If I recall correctly, the white wire is used for the rear PRO clutch when and if it is installed. Without a rear PTO it is not used. Something else to check it the relay on the LH side of the console. A bad relay or bad ground at the relay can cause intermittents as we as could a bad PTO switch on the dash.
On a couple of my diesels, I also had an intermittent PTO. In each case it was something else that cause the problem. On the first time I had the problem, the field coil itself of the PTO would open up when hot after about and hour and a half of mowing. When it cut out, I grabbed my meter, disconnected the connector for the clutch and measured the resistance while hot and found it open. As it cooled, it would start to regain continuity again. This one only happened once or twice a year but after the 3rd year would happen about every other time while mowing. The next time I had this was on another diesel. This time it would happen after I would hit a bump. I thought I was coming off of the seat, but that was not the case. The clip on the fan bracket was holding the clutch power lead in place BUT the connector next to it would bounce all the time. It eventually broke the wires off of the connector inside the insulation. When I connected the meter as int he photos, one wire felt real flimsy and power was still applied. A little pull test on the flimsy wire revealed the broken conductor as the insulation slipped off the crimped connector. The last time I had a problem, the connector for the reverse safety switch by the hydro lever had a bad crimp and was actually melting the insulation. A new crimp fixed that one.