Off of the magneto there should be a little wire most likely green this wire is what shorts to the frame and causes the spark to stop. Check and see if shorting that to the frame shuts it off if it does then it is eather the switch or a broken wire to the switch or a bad ground. To get the the magneto your going to need to remove the flywheel cover and it is on the side of the flywheel with the wire going to the spark plug.
Cody, June 2007
