Briggs & Stratton Ingnition woes?

I have inquired a B&S motor on a log splitter. I believe the motor to be in good shape mechanically but there are some doubts electrically. I am not receiving a spark. I need to know what is involved in this. I know about the magnet on the flywheel creating voltage within the coil but there is a wire coming off of the coil to a ground lug and along with it is a wire that leads to another small box mounted on the side of the motor. There is another lead coming out of that box that went to a switch and the wire coming out of the other end of the switch went to a mounting bracket. Is this just a ground loop for a shut off? Please assist. email to pgapew@hotmail.com