Ignition Wiring Problem

[nastyquedawg]

I am rewiring my boat becuase the previous owner had splices everywhere. The motor is a 1988 88hp Johnson.

My question is shouldn't there be a direct wire coming from the fuse panel to the ignition switch for 12 volts. The only wires that should be connected to the tach is the purple, black, gray wire and a wire for the light. This is coming from the wires on the wiring harnass. The previous owner had a 12 volt lead coming from the battery to the tach. Curently my tach is not working.

 

[metriccrescentwrench]

Re: Ignition Wiring Problem

The purple wire is +12 volts, and is energized when the key switch is in the run position.

As far as the ignition switch, it gets +12 volts on the "B" terminal through a purple/red wire from the engine.

If you can't find a wiring related reason why your tach isn't working the next step will be to check your engine's rectifier, tach won't work with a bad rectifier. Also, if the rectifier is bad your charging system won't work properly, so you should keep an eye on your battery voltage.

 

[Joe Reeves]

Re: Ignition Wiring Problem

The main 12 volt supply wire would be connected to the "B" terminal of the ignition switch. This wire is fused at the engine in one of the smaller red wires, a short distance leading from the starter solenoid.

The purple wire leading from the tachometer should be connected to the "A" (accessory) terminal of the ignition switch. This would allow voltage to be applied to the tachometer only when the key is turned to the ON or START position.

Your engine could have either type rectifier installed, a water cooled unit installed directly on top and to the rear of the flywheel OR a smaller three wire unit attached to the starboard side of the powerhead near the wiring terminal strip. Which one do you have?