Farmall Cub

I have been trying to determine what has been causing my 1250 to drain the battery while running. I tested the output from the charging system while running and it all appears to be working as required. Someone suggested the PTO could be causing the problem. I noticed that after a full charge and a good hour when cutting grass the tractor will start to die, until I turn the PTO off, then it comes back to life.
If it does die ,the battery is usually dead. Been thru a battery every season for last couple of years and generally have sidelined the 1250 due to this issue. Have to charge the battery everytime I what to use it. What is going on?

Sounds like a short in the PTO. Does it do this same behavior when not using the PTO?
Alternatively, your charging system also may not be producing enough amperage to adequately supply the requirements of the electric PTO. The charging system should be able to supply 15 amps.
Perhaps one of the pickup coils are not functioning???

Since I haven't just driven the tractor around to see if it would die after awhile. Cant be sure. I am mowing with it until it starts to die and then shutting off the PTO, it will come back to life. I will test for a short in the PTO since it seems to be causing the battery to drain. Sounds like the charging system by itself cant provide enough power to keep the PTO engaged and running the tractor simultaneously

Sounds to me like the charging system is NOT working properly. The PTO is an electromagnent, and draws a ton of current in order to stay engaged. Chances are, if you drove the tractor around long enough without the PTO engaged, it would drain the battery too, just take a lot longer. When your tractor is running at wide open throttle, you should see about 14 to 16 volts at the battery terminals. If not, then the charging system is not working. If it's reading less than 14 volts, even 13 volts, it's bad. Most likely its the voltage regulator that is bad, and it is an easy fix, two screws and 3 spade connectors, and you're off to the races.

Here is a copy of the wiring diagram. You can ignore my notes, as I was trying to test the PTO switch when I copied this originally.

I don't use this this 1250 hydro tractor very much, but I would like to fix the battery drain issue. After reading a couple of other posts and doing to all the appropriate tests I pretty sure my charging system is working properly and my PTO clutch is worn and draining the battery prematurely. I rebuilding or repairing a worn PTO possible. A new one seems to be running around $250.00