Tachometer wiring for 1979 Merc 90ph

[slyem2002]

I see from my repair manual most shift boxs have a front plug where the tachometer can plug in. Mine doesn't have this, so what model tach and/or adaptors can I connect a tachometer for my motor or switch box?

1979 Mercury 90hp v6 serial # 5160567

 

[ricksrster]

Re: Tachometer wiring for 1979 Merc 90ph

Teleflex tachs available anywhere, even iboatscom.. Set the tach switch on the back to 6P. Run a wire from IGN post on tach to key on wire on IGN switch. It will be white or purple. From the SEND post on the tach run a wire back to the motor and connect to either yellow wire post on the rectifier. Ground wire connect to ground somewhere in the dash or ignition switch. LIGHT post on the tach connects to your navigation light wiring.

 

[Chris1956]

Re: Tachometer wiring for 1979 Merc 90ph

Slyem, If your MerControl has a three wire plug on the front of it, these wires are intended to operate your tachometer. You can buy a molded rubber male plug which mates with the plug on the control. Run the white wire to the tach Ign connector, the black wire to the tach ground and the brown wire to the tach sender connector. Check at the motor to see that the brown wire is connected to one of the yellow stator wires, at the rectifier. It should be in your motor.d