[atc250rboy]

I frist would change the plug.2)follow the plug wire back to the coil,find the two wires that connect to the rear of the coil and follow them back and check for loose or broken wires,also clean the2 wire connection on the coil.3)Do you have a on/off/kill switch check the connection.4)Check to see if the guy you bought it from put a toggle switch somewhere in-line on the positive batt. wire.5)Check the electrical box for broken/disconnected wires.Hope this helps.