tach not working

[almosthere]

tach on 1996 125 mercury isnt working,how do you tell if its the gauge or wiring on motor.how do you check,what kind of meter. thanks for any help john

[boats.net]

Check for 12 volts between purple and black wires at tach with key on, would need a peak reading voltmeter to test voltage at gray wire as rpm's increase the voltage should increase.

[almosthere]

tach

the volts do raise as i give it throttle,almost a volt at half throttle.does that mean a bad tach or something else. thanks john

[boats.net]

Hard to say unless you are using a peak reading voltmeter to test but yes it is probably a bad tach.

[almosthere]

thanks john