3 Wire tach

[87Newman]

I have a 74 Evinrude outboard 85 hp. I have a tach in the boat with 3 wires that were cut. Does anyone know where they might connect to on the motor. The wires are 1 White, 1 Brown with green stripe and 1 Black.

[ADK_Boater]

Having a wiring diagram for that specific motor can't hurt.
Hopefully someone here can provide you with the info.

I have a '72 Johnson 85 hp, but there could be differences in wiring color codes.

Black should be ground.
That leaves you two to deduce.
I can tell you the grey wire in my wiring harness is for the tach.

Hopefully someone has the info in the next bump.

[Sixmark]

Odds are with a 3 wire tach that you have 1 ground, 1 signal wire from the motor, and 1 wire for the light in the tach. look to see if any other gauges were attached to any of those wires, often times they will share common grounds and power for lights.