I had this issue before on a different model, fuses were corroded and wouldnt energize the stop solenoid. I would check the solenoid/connectoins first.
There are 5 pieces to the electric stop puzzle, ignition switch, fuse, wiring stop solenoid timer, and stop solenoid.
The timer activates the solenoid on a power down for approximately 5 sec, if I remember right.