Tachometer hook up

[dubman]

My boat had a tachometer in the dash when I bought it but it wasn't working. It was all hooked up so I presume it worked at some point. I have checked all connections and even bought another tach in case this one was broken. I have hooked the ground and live wires per directions and the gray one to its post. Still no reading when I turn on the engine.

Not sure if I have set the dial on the back to the right place. I have a V8 so I set it to 8. When I turn the key I get a bump on the needle showing me it's getting power.

My question is where does the grey wire hook up to the engine so that I can run a direct line back to it and check the tach. I feel like there must either be a break in the gray wire or its not hooked up to the engine correctly. I am including a pic of the engine so as maybe someone can guide me to the right hook up spot using the pic as a reference.
THX
K

 

[Howard Sterndrive]

Re: Tachometer hook up

grey wire goes to the (-) terminal of the ign. coil on the engine end.

here's the schem.
http://hhscott.com/evinrude/images/wiring/73_OMC_V8_all_big.jpg

 

[tazrig]

Re: Tachometer hook up

Dead center in the way back of your engine is brown plastic cover (distributer cap) with 9 black rubber wires coming out of it. Follow the center wire from the distributer cap to the coil. The grey wire goes on the "-" terminal of the coil. Judging by the age of the motor you probably just have a corroded connection somewhere in the line. Hopefully a new gray wire from the coil straight to your tach will fix the problem.

 

[dubman]

Re: Tachometer hook up

thx guys. I'll check that out. Brilliant!!

 

[dubman]

Re: Tachometer hook up

Dead center in the way back of your engine is brown plastic cover (distributer cap) with 9 black rubber wires coming out of it. Follow the center wire from the distributer cap to the coil. The grey wire goes on the "-" terminal of the coil. Judging by the age of the motor you probably just have a corroded connection somewhere in the line. Hopefully a new gray wire from the coil straight to your tach will fix the problem.

just checked the ign coil and found that there is only one wire going from the "-" back into the distributor. Thats the problem I presume. Now I'll see if maybe there is a loose gray wire back there that should be connected or just run a new one. Do you know what gauge I should use for a new one, 16?

 

[Don S]

Re: Tachometer hook up

Looks old enough, that it may not be gray. That is the BIA color coding system (83 or 84) color for the tach, your engine and drive looks a lot older than that.

Just get a long wire and hook from the - terminal of the coil and the S terminal (or what ever it's called on your tach) make sure the tach has good voltage and ground to the + and - terminals of the coil and run the engine and see if it works.
Then you can go searching for the correct wire at both ends.

 

[dubman]

Re: Tachometer hook up

will do, I'll report progress tomorrow. THX

 

[dubman]

Re: Tachometer hook up

Hey guys, wanted to say thx again. That was it. The tach is now operational.