You can just put your switch on the handle bars right at easy access.. If the motor hangs wide open or something, it's nice to have the button RIGHT AT fingers reach...
The wire just grounds out to the frame or motor wherever.. That engine is old enough to be points, but may have been converted to EIC..
Typically you don't have to remove the flywheel or whatever, as there SHOULD be a spot somewhere on the engie, where a wire is already ran out to a remote location on the engine, so you are allowed to shut it down via the engine controls..
On your engine, it will be a stud underneath the gas tank.. There should be a prong with a little stud where you can bolt down whatever other wire you want to attach to it.. I always unhook that thing anyways, because if you have the throttle setup so as it's pulling ALL THE WAY back to zero, when you let off the throttle, it would kill the engine, because ALL THE WAY shut down is (turn off) on small engines... When the throttle comes all the way back to zero, it makes contact on your prong thing,and grounds out your ignition system.....
So I unhook it there, then tie on another 4 feet of wire, then snake it up to my handle bars... Then just bare a wadd of bare wire, and a good clean spot on the handle bars.. and mash the wad of wire down to kill it...
You need to find your wire.. :laugh: it's either under the gas tank, or someone rerouted it.. Then you'd have to take the pull rope cover off and find him in there wherever he went..