Tachometer question

[carbineone]

I am trying to hook a tach up to my 1974 Evinrude 50HP Lark and my question is that on the key switch is there a terminal to hook it too or do you have to run a new wire from the motor up to the tach?If you have to run a wire from the motor where do you hook it up to at the motor?I read a old post on a bigger HP Johnson here and it says theres a place on the switch..Please help if you can...Thanks

 

[carbineone]

Re: Tachometer question

Heres what terminal I have on the back of my switch. A B two Ms and a S. I was reading past posts on hooking these up and everyone mentions a gray wire to the tach feed but I see no gray wire and no factory plug either as they talk about.So which terminal feeds the tach? I am guessing one of the terminals with the Ms but have to be sure and which one...Thanks

 

[carbineone]

Re: Tachometer question

Update.I believe I found the Gray wire coming off one of the M terminals.And my tach itself has a yellow and a gray coming out of it if this helps...

 

[carbineone]

Re: Tachometer question

Anybody?

 

[Barnacle_Bill]

Re: Tachometer question

There should not be a gray wire connected to the switch. The M terminals is what allows you to turn the motor on and off. There should be a gray wire coming out of the harness going back to the motor. This is your tach signal. Power for the tach is normally got from the A terminal on the switch so it works only with the key on. Battery ground is the only other connection you need for the tach.

 

[carbineone]

Re: Tachometer question

thanks for answering.Yes I have a gray wire that comes up to the control box so I have that part figured out.But My tach is a old original from the same period and it has a yellow wire and a gray wire coming out the back.I assume the gray one goes to the gray on the back of the tach and yellow goes to acc on the switch?Then a ground to the chassis so to speak...Thanks

 

[carbineone]

Re: Tachometer question

I think I amy be figuring out why this tach will not work.Its a airguide and its marked 6GH and 1029 model number.The tach came off a larger 85 HP in the same era but maybe not the same ignition system.If someone knows by those numbers if it will work on my 1974 Evinrude 55HP Lark let me otherwise someone can have the damn thing...Thanks