My new to me, used GT2550 has me puzzled.  I can start the engine with the PTO in the off position, but the blades start turning when it cranks up.  I can pull the PTO switch to the ON position, but the blades stop turning.  It's like the PTO clutch is wired backwards.  The wiring connectors are one-way and cannot be turned around.  I was wondering if someone in the past had changed some wires in the connectors.  HELP!??