Small Engines (Lawn Mowers, etc.): Electrical PTO, ohm meter, safety switches

Question
I have a Craftsman GT 5000 yard tractor model # 917.276022 with a Kohler Pro 25 engine. My Father-In-Law was mowing recently and when he went to reengage the mower blades nothing would happen. I have tested the switch with a volt meter and also the wiring down to almost the clutch, I receive voltage thru both. I am starting to guess the electric pto is bad but wanted a real opinion as to what to do next. If I need to remove the clutch is the bolt a standard thread (left to loosen)or can I check something else first? Also does anyone know where I can get a repair manual for the tractor.  Thjanks

Answer
For the manual try Sears directly.  Some manufacturers did not write service manuals for their products to hold down cost.  Kolher does have manuals for their engines and can be ordered from their web site.  Try to find the engine model and serial number.  If there is only a Sears number go to Customer Care and ask which engine thy used based on their model number.

You can test the clutch on the unit.  You will need a fully charged battery.  Disconnect the clutch from the wire harness. Apply 12 V to the clutch and it should activate.  

You can measure the resistance of the windings too.  Using a digital Ohm meter and touch the two prongs in the clutch plug.  The reading should be 0.03 ohm's.  If you use an analog meter you would not be able to measure anything that small.  

If the clutch tests ok check the seat switch.  The seat switch and PTO switch are in the same start circuit.  The PTO is a double pole double throw switch.  Meaning that the switch has two switches in it.  Both have to operate.  Use a continuity meter to test the switches.  Be sure the meter has a fresh battery in it.

From there think through the start circuit.  You have to be sitting in the seat with the PTO off and brake on. 12V DC travels from the battery to the solenoid post.  The a 12 V charge goes from the small tab om the solenoid to all safety switches in the circuit and back to the other small tab on the solenoid.  If all is good the solenoid engages and 12 V DC goes to the other post on the solenoid and on to the starter and then to ground.  12 V should not go to ground anywhere along the circuit.  If it does that could be your problem.  Clean all connections and look for bare wires touching the frame close to where a belt or pulley runs.  Do not forget the key switch or the fuse.

Good luck.