Tach Question

[Alpinegold]

I have a 1979 Johnson 115h/P with 115 compression spread evenly across all 4 cylinders. It's been rebuilt and sitting on a 1978 Ranger v178 that I have restored. My Tach does not work. My Crymar book shows only a grey wire going to the Tach. The Tach actually has 4 wires coming out and I pretty sure one of them is jumpered light wire. I have tested rectifier and it shows good. I have the switch set to 4 cylinders. Do I need to buy a new Tach?

 

[ezeke]

Re: Tach Question

The tach needs three wires to function and the fourth if you want the light to work off your light switch.

The gray wire is separate from the ignition wiring but is contained within the same harness. It runs from one of the yellow wires (post 3) on the engine terminal block to the remote control. On the original side mount control, the wiring terminates in a three pronged amphenol plug below the ignition switch.

Positive voltage comes from the ignition switch "A or Accessory" post via a purple wire.

Negative black wire ground comes from the smaller "M" post on the ignition switch.

These three wires are all connected to the amphenol so that the tachometer may be pugged in if you have the tachometer harness.

The light wire is blue and could be connected to one of the guage light wires, also blue.

The correct setting on the back of the OMC/BRP or Teleflex outboard tachs is 6p.

To see the remote control wiring, go here and scroll down: http://continuouswave.com/whaler/reference/ignitionSwitch.html