1979 Two wire tach / trim gauge

[CLB35]

Has anyone come across an old two wire tach (yellow & black)? I know the grey coming from Eng (85hp Johnson V4) needs to be present as well as a ground but nothing i'm finding shows use of 12V switched from ign? Also on a trim gauge when I started this project gauges were all there but wiring is a mess, I have found most all leads from senders except the trim anyone know where that wire originates? Thanks in advance for any advise. - Corey

 

[finish line 88]

Re: 1979 Two wire tach / trim gauge

I have an Evinrude 2 wire tach and I was told that the gray wire should be 12 volt and of course the black is a ground. My gray only measures 8 1/2 volts and the tach only reads up to about 2000 rpm's. I had it on another motor and it worked fine.

 

[CLB35]

Re: 1979 Two wire tach / trim gauge

I haven't tested the voltage on that wire I came across it by accident, under the control 4 wires dropped out facing down power,ground, 12v, Ign switched hot and a white wire (haven't traced that yet but believe its to the choke) anyhow I noticed a cut grey wire so I took the bottom of the control off, sure enough that was it. I looked at what grey was said to be, soldered a new wire in and ran it to the console. It just seems odd that the wires out of that Tach are yellow and black no ign power. There is a light as well but separate socket and bulb wiring all together.