I believe the issue is solved. It was a combination of the 3 way seat switch, the PTO clutch lever switch and the HST pedal switch. Ran it for a few hours today and all seems well. I want to thank everyone for their input on the B2601 shutting down issue. Hopefully this will help someone else in the future.Have you checked the forward/reverse pedal neutral position? These tractors have problems with the pedal not returning all the way to neutral when released. That would cause the tractor to shut off when you stand up since it thinks it is still in gear.