Is this a 4 cycle engine or 2 cycle? What kind of engine is it? The only wire that should be on this is the kill wire. Does this unit have a key switch on it? The wire should come from the coil and go to the kill switch. The kill switch may not be grounded at the location it is mounted and may have a wire that goes to ground it.
Go to this link below. The wiring diagram is listed under the drivetrain. I think the white wire is a ground wire. You will need to enter your model number and yours would be the second one with the 800 serial number.
Here is the picture of the wiring