hey, I have a LX 172 and after running for about 20 minutes the blades will cut off. When the blades cut off you can cut them off at the switch and back on and they work for another 3 to 5 minutes. I replaced the electric clutch and postive battery cable. The same thing is still happening. Any sugggestions? Could it be the Switch or the Seat Sensor? How is a easy way to test?