What excatly do the safety switches do? I have a Craftsman LT 1000 with a 17.5 hp engine and it states in the manual that there are three switches. Do they take power off the fuel shutoff solenoid or shut the spark off to the spark plug?

There are apparently three safety switches on this mower (seat - brake - mower blade clutch). If one of these shuts the motor off, what is it actually doing, shutting off the gas (fuel shutoff solenoid) or the ignition (spark plug)?

Hi,
It is grounding out the ignition module/armature.
Peace,
Clarke

Let me make sure I understand. If one of the switches were grounding out the ignition module/armature, would the starter still turn the engine over but just no spark at the plug?

Hi,
It could depending on how the wiring harness is designed. A very few Craftsman mowers have the solenoid permanently powered and there are triggered by the presence of a ground circuit themselves. Not the best solution, but I have seen a number of models. I always read the schematic if I am given the model number, the manual is available, it contains the schematic and the problem is electrical.
Many of the problems here are either electrical or fuel related.
Peace,
Clarke