Tachometer Wiring Troubles

[mmajor97]

I am currently working on a 1985 Evinrude 115. I just got a new tachometer and am trying to get it to work with no success. I replaced the rectifier as the other one was not charging the battery. I am currently pulling a little over 13.5 volts on the battery now while running and 12.4 volts while sitting so I know the new rectifier is working. I have good 12v and ground wires hooked up to the new tach. I hooked the "grey" wire up to the SND terminal also. Still nothing. I tried hooking the SND terminal directly to the grey wire coming from the new rectifier. Nothing. The dial on the back of the gauge is set to "6". I am at a total loss here.....any thoughts?

 

[Joe Reeves]

Re: Tachometer Wiring Troubles

Sounds like you have everything wired properly. However, grabbing at straws.... just to eliminate something I've encountered a few times, run that tachometer ground back directly to the negative terminal of the battery. If that bumps the tachometer into action, you're originally cutting into a ground that is carrying voltage out from some accessory.

 

[mmajor97]

Re: Tachometer Wiring Troubles

I will certainly give that a try. So far I can't get the tach to even so much as quiver other than when it resets to 0 when the switch is turned on.

 

[mmajor97]

Re: Tachometer Wiring Troubles

Just sitting here pondering this issue and thought of another question. Would the tach have to be hooked up to the same battery that the motor is running on? I am currently running all gauges and accessories on a separate battery. I an thinking that since it is grounded off a different battery that the circuit is not being completed. Am I on the right track or just going clinically insane?

 

[Haffiman]

Re: Tachometer Wiring Troubles

If both batteries run a common ground, both grounded on the engine, it should not be a problem.

 

[mmajor97]

Re: Tachometer Wiring Troubles

Could be on to something then, the batteries are completely separate. My ” accessory” battery is not connected to the engine whatsoever.

 

[Joe Reeves]

Re: Tachometer Wiring Troubles

Tach must be grounded to battery that is operating engine.

 

[emdsapmgr]

Re: Tachometer Wiring Troubles

The 1985 control box should have a short 3-wire plug dangling from it. That factory pigtail is for the tach. Do you have your tach hooked up to those wires?

 

[mmajor97]

Re: Tachometer Wiring Troubles

I tried hooking it up that way at first only to find that the prongs on that plug wereabout rotted completely out. I am trying to bypass the plug.

 

[bktheking]

Re: Tachometer Wiring Troubles

It it doesn't work at the plug try running it directly off the rectifier itself, wouldn't be the first time i've heard of a broken wire going to the controls. I had to do this on my merc.

 

[mmajor97]

Re: Tachometer Wiring Troubles

That was the plan, if I can just get through this for letter word called ” work” I will give it a shot when I get home. Thank all of you for your knowledgeable and fast responses.

 

[bktheking]

Re: Tachometer Wiring Troubles

Ten for

 

[mmajor97]

Re: Tachometer Wiring Troubles

Just got home from work, hooked the tach directly to the rectifier. Bingo! Now I guess its time to go get some wire and make me up a little wiring harness. Thank you all for the help!

 

[bktheking]

Re: Tachometer Wiring Troubles

Maybe just that the wire from the harness isn't hooked up, trace your wiring, if you see a wire going nowhere , I think gray wire, that could be it.