OMC Tachometer Wiring

[ruddy]

I've discovered old threads that explain how to hook up tachs with the following wire colors:

Purple: Switched power source
Black: Ground
Gray: Pulse
Red: Lighting

Mine, however, has Purple, Black, Gray and BLUE wires. How do these hook up?

Thanks.

 

[DJ]

Re: OMC Tachometer Wiring

Grey=signal.

Black=Ground.

Purple=switched.

Blue=lighting.

I've found that to be true on almost all aftermarket tachs.

 

[ruddy]

Re: OMC Tachometer Wiring

Grey=signal.

Black=Ground.

Purple=switched.

Blue=lighting.

I've found that to be true on almost all aftermarket tachs.

Thanks. I suspected that, but I wanted to make sure. What terminal on '74 70HP Evinrude should the pulse come from? I see two, one with a gray wire and one next to it with a gray/yellow wire.

 

[ricksrster]

Re: OMC Tachometer Wiring

Either one. http://ww2.tflx.com/PDF/99320.pdf

 

[ruddy]

Re: OMC Tachometer Wiring

Thank you.

 

[eatropefish]

Re: OMC Tachometer Wiring

Either one. http://ww2.tflx.com/PDF/99320.pdf

There appears to be a misprint in the schematic. The ignition feed and the send feed are mislabeled on the tach. Are they not?

 

[Silvertip]

Re: OMC Tachometer Wiring

The schematic is wrong. The SEND terminal is not switched +12V as shown, that terminal should have the pulse line (SEND) from the engine. The IGNITION terminal should have switched +12V on it. It doesn't matter what the orientation of the terminals on the tach is. The labels on the tach are correct. The sources are wrong.

 

[eatropefish]

Re: OMC Tachometer Wiring

Yes, however you want to look at it the schematic is wrong. The directions say do not deviate from the wiring but if you follow the schematic you're wiring it wrong. I wonder if Teleflex is aware of this error.