Tach wiring

" Can anyone tell me where I s

" Can anyone tell me where I should be hooking up the three wires that come off the tach? I believe the black is ground, the purple goes to the purple from the engine end of the wiring harness (from the rectifer) and the purple off the ignition switch (marked I on the back of the ignition tumble)?
The one I am really not sure of is the grey w/tracer? Does this go to constant power or ignition power or??? Help, this is driving me nuts!!! "

"Jeremy..... It would help if

"Jeremy..... It would help if we knew exactly what year, make, and hp engine you were refering to.

Tach "Black" goes to "Ground".

Tach "Purple" goes to a 12 volt source that is hot only when the ignition key is in the "On" position. (NOTE.. Purple has absolutely nothing to do with the rectifier!)

Tach "Gray" leads to the rectifier yellow wire that has a gray stripe. There should be a "Gray" wire leading out of the instrument wiring harness that would attach to the "Gray" wire leading from the tach. However, make sure that the other end of that "Gray" wire is attached to the same terminal block location that connects to the rectifier yellow/gray wire.

Joe "

" Is this the same for a 1967

" Is this the same for a 1967 Mercury 650 outboard? I cannot get my tach to work with this wiring. I tried both wires coming out of the rectifier. This motor's wiring harness does not have a tach wire. However, I can get a dwell tach to work hooking one wire to ground and one to the magneto. "

"John.... I have no knowledge

"John.... I have no knowledge of the Mercury wiring system. Back up to the previous page, go to the extreme bottom of the page, click on that "Start New Conversation" button and address your question to "Tony".

Joe"

" Thanks Joe, I didn't thi

" Thanks Joe, I didn't think that the year/make etc was needed, sorry. It is a 1991 Force 70hp with the Mercury ignition.

I have black to ground, there is a purple, black and grey w/tracer off the tach. If I understand you correctly, I should connect the purple to the purple lead off the ignition (marked I on the ignition tumbler), and the grey w/tracer to the grey that comes off the rectifier? It sounds straight forward but the wiring harness that came with the boat is not the right one and there are not the same colours that are at the engine end or the dash end!

I will try what you suggest and let you now, thanks. "

Jeremy.... Re-enter your ques

Jeremy.... Re-enter your question and address it to "Tony's" attention. I should think he would have the answer. I jumped the gun thinking your problem was a OMC thing.

Joe