OMC Wiring Harness Incompatibility

[frosted]

I have mounted a '76 Evinrude 40hp to an '80 model Lowes aluminum with OMC single handle controls. Problem at hand is that the pins on the OMC wiring harness and the Evinrude motor don't match 1 for 1, resulting in a dead miss on one cylinder when the motor is running and OMC harness is attached. Detachment of the harness with the motor running resolves miss issue. Can anyone tell me if an adapter exists that will allow me to matchup the pinouts on these two harnesses? Or am I better off trying to find another harness for this '76 model motor? Thanks.

 

[rodbolt]

Re: OMC Wiring Harness Incompatibility

is the motor harness a black plug? is the control box harness a red plug ?

 

[Walker]

Re: OMC Wiring Harness Incompatibility

I'm at a loss here. I don't see what would cause one cylinder to not fire due to the harness plug.

 

[rodbolt]

Re: OMC Wiring Harness Incompatibility

cause of the differences in the kill circuit wiring.

 

[frosted]

Re: OMC Wiring Harness Incompatibility

Yes, Rodbolt, you are correct red and black harness plugs.

 

[rodbolt]

Re: OMC Wiring Harness Incompatibility

it will work but you have to Isolate the kill circuit. the red plug engines have a black lead and a black yellow lead and killby appling the black ground to the black yellow. the black plug kills by appling the two black magneto coil kill wires together. its possible to cut up the wiring to make it work.

 

[frosted]

Re: OMC Wiring Harness Incompatibility

Thanks for the quick replies. Rather than cut up the molded harness, if I were to circumvent the factory harness wiring and run a separate kill circuit from the OMC control switch, back to the motor, am I following correctly in that the kill circuit needs to ground both coils on the motor? A simple two wire circuit with a single lead from each sparkplug coil running back to the on/off OMC switch, which when completed connects both coils to ground? My apologies if these questions are elementary, but this is uncharted territory for me and I want to ensure I don't create bigger problems attempting to resolve the primary issue.

 

[rodbolt]

Re: OMC Wiring Harness Incompatibility

hello<br /> untape the red plug harness. splice a connector for the black and the blk yellow. untape the black plug. find the two kill circuit wires. should be blue and blue/white. tie the two together.you may have to remove the ground jumper from the control box frame to the switch if anything is grounded at the box. this will also isolate you from the kill circuit .<br />you will be amazed at the zap the wires can give <br />or you can remove the wires from the M terminals on the keyswitch and run two wires, one from each m terminal, to the blue and blue white wires aft of the black engine plug. your choice

 

[frosted]

Re: OMC Wiring Harness Incompatibility

Many thanks for the explanation. I'll give it a spin as soon as the weather clears. -Ed Frost