Repairs electric cluth wont engege when hot

I own a model 917.275685 lawn tractor. lately I have noticed that if I shut off the pto after a bit of mowing to cross an obstacle it will not engage again. I was surprised to find that it worked again later after everything cooled down. I tested it by doing the same thing. mow for a bit and shut off the pto then try to re-engage. same thing. I have checked the clearance with a feeler gauge and its about 12-13 thousandths. before replacing it outright I though I would check here and see if there are any pearls of wisdom. if replacement is the answer how is the best way to stop the engine from turning when I try to turn the main bolt on the clutch? Thanks in advance for the help.

My guess is you have what is called a hot short or open either in the PTO clutch or PTO switch. A hot short is where heat cause the circuit to short to ground. A hot open is where the circuit actually separates due to heat expansion. To test the clutch, the next time it happens, unplug the power wire at the clutch and with the engine not running, but the key switch in the run position and the PTO switch in the ON position, test to see it you have power going to the clutch. If you have power, plug it back in, start the engine and see if the clutch engages. If it does not engage, bad clutch. If you had no power at the clutch plug, you will be looking at a bad PTO switch. Testing the switch is not as easy unless you can get a wiring diagram of your unit or diagram of your switch, because there are many different switches. You may also have a hot short or open in the wiring harness, but these are even harder to track down without a diagram and electrical experience.