1977 85 horse Merc Tach install

[McMudpuddle]

Anybody know what wire too tap into to get the correct signal for the tach?
Thanks

 

[achris]

Re: 1977 85 horse Merc Tach install

In the front end of the control box is a 3 pin connector. That connector is for the tacho harness. It has +12 volts, ground and the tacho signal, which originates from one of the charging coil wires where it connects to the rectifier, it should be gray in the engine.

Chris.............

 

[Chris1956]

Re: 1977 85 horse Merc Tach install

Actually Chris, on those old motors the tach wire is brown. The grey wire runs the choke.

 

[achris]

Re: 1977 85 horse Merc Tach install

Actually Chris, on those old motors the tach wire is brown. The grey wire runs the choke.

My bad, quite correct....