Small Engines (Lawn Mowers, etc.): Lawn Tractor PTO, cement block, safety switches

Question
I Have a Craftsman 16.5 HP lawn tractor, model 917272010.  The PTO was replaced a couple of years ago as was the wiring harness nearest the PTO.  We had a problem with the PTO engaging recently, and it appeared to be a frozen pulley.  We replaced that, the PTO "hesitated" then eventually engaged.  It has worked well since.  Last week, I had the PTO disengaged, but the mower was running.  I got on, backed up, the mower hesitated (as if it were stalling), and when I pulled the PTO switch, nothing happened.  I have since checked for power to the PTO which it does have.  We tried jumping the safety switch with a wire to see if the switch was bad.  It didn't help, but thereafter, whenever the PTO switch was pulled, it starts to stall, even though the safety switch was replugged in.  Previously, I had a cement block on the seat, and it did not stall when the PTO switch was pulled.  My question is twofold:  Why would it now stall when the PTO switch is pulled?  Why won't my PTO engage?  I read your previous email regarding Debbie's PTO.  The Sears parts site is not detailed enough to trace the wiring and/or identify other safety switches.  Thanks for any help.

Answer
Hello Doreen:

It is Possible that the Problem is the Engine is Not Charging with the Required Voltage or a Safety Switch is Bad. With the Engine Running at Full Throttle; What is the Voltage at the Battery with the PTO Switch Disengaged? What is the Battery Voltage with the PTO Switch Engaged or Does the Battery Voltage Drop when the PTO is Engaged. If the Battery Voltage Drops Below 10.5 VDC when the PTO Switch is Engaged, then the Stator is Not Charging Properly or the Voltage Regulator is Bad. From your Description it Sounds like the Seat Safety or the Safety Interlock Relay May be Bad. The Interlock Relay in Near the Ign Switch. I Usually Follow the Seat Safety Wires and Locate the Relay. If you Hit a Snag or this Does Not Correct the Problem,  I am Here if You Require More Assistance. Hope this Helps. Let me Know What Happens, Please. May the All Mighty Bless You and Yours. Thanks.

Good Luck

Respectfully

John

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Respectfully

John