1987 Johnson 175 tach problem

I have a 1987 Johnson 175. The tach doesn't work when the engine is running.It seems to power up when you turn on the switch.I was curious as to which wire sends the signal to the tach.Any input greatly appreciated! Thanks

Re: 1987 Johnson 175 tach problem

Hi kid, welcome to iboats!<br /><br />The signal wire comes from the rectifier. It'll be a yellow w/gray stripe back on the terminal strip on the engine block. Make sure you check the connections at the tach terminals also. The purple wire to the tach is from the ignition and provides power. Black is ground. <br /><br />Have you had any trouble with the engines charging system? Sometimes a loss of tach signal indicates a faulty charging system. If your not aquainted with trouble shooting, best thing to do is A: Beg, bum or borrow a known good tach and try it, B: take it to a wrench for trouble shooting or C: Get a manual (OEM preferred) and learn the "how to's" your self.<br /><br />Don't hesitate to post if you have any more questions.....thanks.

Re: 1987 Johnson 175 tach problem

Isn't the tach wire gray OBJ?

Re: 1987 Johnson 175 tach problem

Yep. It's yellow w/gray stripe at the block and changes to solid gray. If he is using the three wire harness that plugs into the control box, it will be gray. Thanks for pointing that out Walker...