how to wire tach

[job-grecos]

I have a 1989 v4 110 johnson. Recently picked up, there are no wires to connect to the tach gage in the dash from the power head. I have the manuals for the motor but I do not understand what part of the motor supplies the RPM information. Someone cut a lot of wires so I am having lots of fun!

 

[Joe Reeves]

Re: how to wire tach

Does the tachometer have wires extending from it, and if so, what color are they? Or are their simply wiring terminals (screw type usually) on the back of the tachometer, and if so, how are they marked?

Does your rig have a regular white control box which has a three (3) socket connection beneath the ignition switch?

 

[job-grecos]

Re: how to wire tach

They are simple wiring terminals. One has a gray wire and the terminal is marked with an "S" and the other a purple wire marked with an "I". The control box does have the three socket below the the egnition switch.

 

[Joe Reeves]

Re: how to wire tach

That 3 socket connector is as follows:

........O (B) Gray Wire (Sensor)


O (A)........O (C)
Purple........Black
Wire..........Wire
12v...........Ground

You can pick up a tachometer wiring plug from your dealership that has the purple wire and pin installed BUT you will still need to install a Gray and Black wire with the pin to complete the socket assembly. If you can't find anyone to do that job and would want to keep the installation as it should be, I could handle that for you if you so desire.

The alternative is to connect the purple wire of the tachometer to either the "A" terminal of the ignition switch OR any wire that has 12 volts applied to it ONLY when the key is in the ON position, and.........

Connect the Gray (sensor) tachometer wire ONLY to the Gray wire at or inside the control box OR to that Gray wire should it be extended to any area outside of the control box and.........

If a black wire or a terminal marked "G" exists on the tachometer, connect a tachometer Black wire from there to any known ground.

Let me know what you decide and how you make out.

 

[jammer]

Re: how to wire tach

I have a 1989 v4 110 johnson. Recently picked up, there are no wires to connect to the tach gage in the dash from the power head. I have the manuals for the motor but I do not understand what part of the motor supplies the RPM information. Someone cut a lot of wires so I am having lots of fun!

It can seem like rocket science...but read the posts below. It's three wires. Even know that some of these wires can also be used for some of the other guages. You'll do fine..you'll see. I did it. Keep asking if you run into troubles.

 

[hoeser]

Re: how to wire tach

I didn't really want to restart a new thread for this but I am installing a new tach tonight and I removed the old one last night... the new one is not an OMC but is compatible. The OMC actually had 4 wires going into it. I know what 3 of the 4 do, but I have no idea what the blue wire is for... anyone?

I have:

GREY: Signal
BLACK: Ground
PURPLE: Ignition +12
BLUE: ???

 

[Kevin W]

Re: how to wire tach

GREY: Signal
BLACK: Ground
PURPLE: Ignition +12
BLUE: ???

Blue is for the instrument light

 

[hoeser]

Re: how to wire tach

That was my original thought as well however it comes from the control box and the light comes on when the ignition is on which makes me wonder why they really needed a 4th wire for that... they could have just used the purple I+12V feed.

 

[jammer]

Re: how to wire tach

That was my original thought as well however it comes from the control box and the light comes on when the ignition is on which makes me wonder why they really needed a 4th wire for that... they could have just used the purple I+12V feed.

Now that's wild. Now I have a teleflex. Before it was the original that came on my Ranger boat...and even with the three wires it wouldn't turn on the light. Maybe it's something simple like...when I turn on my dash to look at the lights ...it will light when you turn on the dash lights without the ignition.

 

[Forsaken]

Re: how to wire tach

not trying to pop in and bust bubbles but, on my 'rude, i have the pilot control box and i have a blue wire that comes from it and that blue wire is the signal from the motor... i found this out because someone didn't have it on good when i first got it and i took it out on the lake where the wire fell off and it took me about 2 hours to figure out what happened. then i plugged the blue in as the signal and fired her up and you'll never guess what happened... it worked!!, lol.

 

[jammer]

Re: how to wire tach

not trying to pop in and bust bubbles but, on my 'rude, i have the pilot control box and i have a blue wire that comes from it and that blue wire is the signal from the motor... i found this out because someone didn't have it on good when i first got it and i took it out on the lake where the wire fell off and it took me about 2 hours to figure out what happened. then i plugged the blue in as the signal and fired her up and you'll never guess what happened... it worked!!, lol.

Wow! I can see why it took you 2 hours. Heck I thought my boat when I got it had a rig job lol

 

[job-grecos]

Re: how to wire tach

Joe thankyou very much for your help, I connected the wires as per your post and it worked like a johnson!! Anothe subject, I have seen this information on other post but did not under stand them full I hope you don't mind to much if I ask how to do the WOT timing adjustment with out running the motor up to full RPMs. Thanks for all the help so far!