my mtd lawnflite 547 wont start (12 hp briggs & stratton )?

if you can start by bridging starter ,I would suggest investigating wires from the ignition switch to the motor . if your mower has a push button start check that also. check for loose connections , could well be the ignition switch at fault.also iam thinking there must be some inline fuses somewhere or maybe a starter relay perhaps ,not sure,but it must be a pretty basic starter system?.

mech monster
October 2011