Tach Wiring

[mjash]

I have a 1977 85hp Evinrude. I am looking for the pinout for the connector under the key to hook up the tach. Help would be greatly appreciated.<br /><br />Mark

 

[llfish]

Re: Tach Wiring

If you hahve a OMC control box with a rubber electrical type plug just under the ignition switch, there will be three sockets there. With a ohm meter you can find which sockets are the Ground (G), voltage of 12v (I) when the key is ON, and the remaining one would be the sensor unit (S).<br /><br />If you do not have this setup, look for a Gray wire leading from the instrument wiring harness, that is the harness leading back to the engine. That Gray wire is connected to the rectifier at the engine and is the sensor unit (S). The other two.... 12v (I) when the key is ON and the ground (G) would be self explanatory.<br /><br />--------------------

 

[Mark42]

Re: Tach Wiring

If you can wait until tonight, I'll look at the wire diagram and tell you the layout of the pins. Otherwise do like Larry said. <br /><br />Of course the above only applies to the thin control box. If you're control box looks like this.....<br /><br />

<br /><br />....you will have to open the cover and look for the grey wire with shrink tubing on the end to seal it off. Take off the shrink tubing and thread the wire out the bottom through one of the provided holes. If you want access to the ground and ignition wires, you will have to open the entire box to get access to the back of the ignition switch and connect to the ignition and ground there. Be sure to connect to the switched side of the ignition (purple, I think) and not the always hot from battery red wire. That way you will only have power when the switch is in the "on" possition.<br /><br />I'll double check this tonight at home if you need me to or maybe someone else here can verify the colors.<br /><br />Mark