I have a 1991 Johnson 200hp that starting misfiring. Now the ignition switch will not engage starter everytime. Sometimes it will spin the motor but appears to be firing weak. Then the next time you turn the key you get nothing. I checked the battery connections and they are ok. There is about 6 wires attached to the ignition switch that run to the engine in a wiring harness. Is my problem within this wiring or somewhere else?? The ignition switch is new also. Please advise.