Connecting a Tach to my 78 Johnson 115

My service manual refers to a Tach kit and specifies the Gray wire in the remote control unit as the tach wire. I can find no more info on it though. From looking in the forums I can figure out how to connect a Tach but I'm not sure what type of Tach I need or what type of sending unit there is for this old motor. can anyone point me in the right direction?

Re: Connecting a Tach to my 78 Johnson 115

The tachometer operates off of the engine's charging system. A the engine's wiring terminal strip, a gray wire is attached to the screw terminal that leads to a yellow wire that leads to the rectifier. This gray wire is the sending unit so to speak (sensor wire). This gray wire continues on thru ther wiring harness up to the control box and instrument panel where it can easily be attached to the tachometer.

The tachometer that you mentioned in a previous post should work. However, the proper tachometer would be one that would operate off of a 6 pulse charging system, which your engine has. The tach would have a dial on the back of it which you would set to number six (6).

Re: Connecting a Tach to my 78 Johnson 115

Thank you Mr Reeves, perfect answer, just the help I needed.