Do you have a wiring diagram for this model? The engine will not shut off when the ignition switch is off and it will not shut off if someone is not sitting on the seat.
Most likely the kill wire from the engine has become detached from the rest of the wiring. Should be obvious if you trace the wire coming from the ignition coil.
phil_saunders(a)bigfoot.com
Phil Saunders
October 2012
Automatic Answer
We may have found other answers which could help you.
howtomendit.com for free repair help, information and advice.
Try fixfault.com to fix lawn mowers.