Question about replacing tachometer

[TDmanager]

My 1979 70hp has a 2 wire tachometer that hooks uo inside the shifter control box. It has a black wire and a gray wire. All the tachometers that I have found for Evinrudes have three wires. Black, gray and red. Can I use the 3 wire tachometer on my boat by just hooking the red wire to a 12 volt switched power source?

Thanks in advance for the help.

 

[jtexas]

Re: Question about replacing tachometer

purple -- the purple wire from the "A" (accessory) keyswitch post is your switched power source. If you have the OEM control box, there's a socket covered by a rubber boot just below the throttle tension knob that accepts a plug & play tach wiring harness, which I found one of for a reasonable price at basspro a few years ago.

 

[TDmanager]

Re: Question about replacing tachometer

Thanks for the reply. The tach that I'm now using connects to the plug in the contol box. Are you saying I need to find a wiring harness that will plug into my control box that will allow me to connect the 3 wire tach? Can I open the contorl box and connect to the purple wire to power the new 3 wire tach if I can't find the harness?

Thanks!

 

[F_R]

Re: Question about replacing tachometer

Thanks for the reply. The tach that I'm now using connects to the plug in the contol box. Are you saying I need to find a wiring harness that will plug into my control box that will allow me to connect the 3 wire tach? Can I open the contorl box and connect to the purple wire to power the new 3 wire tach if I can't find the harness?

Thanks!

Of course you can do it inside. The 173602 plug just makes it So.o.o.o. much easier.

 

[TDmanager]

Re: Question about replacing tachometer

Now your talking my language... Pictures!

Thanks!