TACH ONLY HAS 2 WIRES

[jamminmaz]

HI,<br />1972 100hp johnson, 1972 16ft fiberform is the boat. I have a wire that comes out of the control box, that runs to the tach, and then on the back of the tach, there is a black wire that is not hooked up to anything. Shouldnt there be 3 wires, or is that black one ground, and the one from the box is power and signal?<br /><br />Thanks

 

[Rockchalk]

Re: TACH ONLY HAS 2 WIRES

I have a Tach question as well somwhat related so will add on here if you dont mind jamminmaz. My 1983 75hp Johnson has no Tach at all. How hard are they to add. Much like jammin... Not sure what you hook them to. Kill two birds with one stone guys... Thanks!!!

 

[fireman57]

Re: TACH ONLY HAS 2 WIRES

Rockchalk do a search on adding a tach. There are a lot of posts on it. Jamminmaz I don't have the answer for you but I'm sure someone will be along shortly.

 

[jamminmaz]

Re: TACH ONLY HAS 2 WIRES

gracias seniors,<br />I tried too, and there are definately lots of posts adding a tach from scratch as well. I know that black wire has to be either key on hot, or ground, but i dont want to put power anything for fear of hearing sizzling noises, and the 'ol familiar smell of burning wires.

 

[dolluper]

Re: TACH ONLY HAS 2 WIRES

black =ground gray=feed tach

 

[rodbolt]

Re: TACH ONLY HAS 2 WIRES

hello<br /> yep a lot of the old OMC tachs were 2 wire. gray is send and black was ground.

 

[jamminmaz]

Re: TACH ONLY HAS 2 WIRES

well, that makes life easy then!!<br /><br />Much love for all of you in this forum!!

 

[imstillatwork]

Re: TACH ONLY HAS 2 WIRES

would't the third lead be a hot for a backlight sharing the ground?