Tachometer Hook up

[doral87]

I have a 87 Doral Grande with a 4.3L 4V, 6 cylinder and omc drive. The original alternator was replaced last year with an MES marine model. The factory tach was connected to the old alternator with two wires but there appears to be no such connection on the new alternator. This was done before I purchased the boat so I do not know much more about how it was set up originally. Any suggestions for re-connecting the tach with the new alternator?

 

[slydog75]

Re: Tachometer Hook up

Tachs usually have three wires. A ground wire, a 12V power wire, and the sensor wire. best thing to do would be to identify these wires and just hook them up in appropriate and accessible locations. The sense wire (on all tachs that I've seen anyway) should go to the negative terminal on your ignition coil.

 

[doral87]

Re: Tachometer Hook up

The way you describe the hook up is how I understand a tach should be connected, but I still can only see the two wires. I am tracing the wires back to see what I can find. My OMC has a electronic shift assist module system, does this change the hook up in any way? Thanks for the input.

 

[mkast]

Re: Tachometer Hook up

Then open the tachometer case to find the third wire.

 

[SPDFRK68]

Re: Tachometer Hook up

In some cases there will be 4 wires signal,power,ground,assy(light) but they should be connected as the afore mentions post stated. power a 12v source ground, signal the negative side of the tac and the assy. wich should be wired in to the other dash lights.