I have a craftsman riding lawn mower model number 917254642 that won't shut off after you shut the engine down it will contuine to run until you touch it with something medel to medel. Can you tell me what may be causing this problem?

So do you mean the engine keeps running after you turn the key to off? What metal item did you touch to what part of the mower to kill the engine?

Hi,
Well obviously it lacks a ground somewhere. I would first check to make sure that all four of the bolts that fasten the engine to the frame are tight, seen that do it. Your description seems to be that you are creating a ground.
Peace,
Clarke