I recently purchased a used unit and they guy had a bolt in the slot locking the PTO 540 lever to the engaged position. I wanted to see if the PTO would stop if I removed the lock bolt and slide the lever forward. In doing so......as soon as I released the HST foot pedal the tractor now stalls. I can get the machine running but as soon as I release the HST pedal she boggs down and stalls. Before I removed that lock bolt everything was fine other than the PTO shutting off. Any info will be very much appreciated.