'76 Merc 85hp Wiring from Engine to Control Box Help

[Dentcrew]

Hi everyone! Really need some help here, when I went to pull apart the wiring harnesses that connect the control box, to the engine harness, the plugs fell completely apart and the wires broke/pulled through, leaving me NO color left on the wires to know which was connected to which. Obviously, the red to red and black to black, but that leaves several more that I have NO clue about. I will just straight wire them, and skip the replacement plugs for now, if someone can PLEASE tell me what goes where. I've attached photos of the 2 harnesses, the one that has the solid only wires, is the engine harness, the other pic with striped wires comes from the control box. Thanks so much!

 

[merc850]

Right from the manual; if yours is really a 1976.

 

[Dentcrew]

I was told it was a 76' as I asked on this forum, the serial number pulls up nothing. but here's a pic of the serial number:

 

[merc850]

It is a 1976 - the wiring diagram should apply.

 

[Dentcrew]

Thanks a TON! Have any suggestions on what to tell a parts place, as they can NEVER find it in their
systems to get me parts?

 

[merc850]

Any Mercury dealer can get you parts with the ser. Nr.; other sites have the parts too.

 

[Dentcrew]

Oddly, I have 7 wires on the engine harness ( don't know if the 7th was hooked up since the plug/pins literally fell apart ), but the diagram shows only 6. The extra wire is white (not shown on the diagram ). Another nightmare, is the wiring harness from the control box, has different colors than the diagram ( purple, yellow/red, yellow/black ). Guess I will have the fun task of figuring what is connected to what so I know what they "Should" be in comparison to the diagram

 

[Dentcrew]

Found the tag on the control box harness shown below. Was trying to find the color codes, as it has striped wires, rather than solid, and different colors than shown in the diagrams. But, with those numbers, I can't find anything. It reads: 84-17247

 

[Chris1956]

It sounds like you have a newer wiring harness on the control. The wiring connection (new to old), should be.

Red to red for battery power

black to black for ground

yellow/red to yellow for starter solenoid

Purple to white for ignition power (may not go to motor on your engine)

Black/yellow to orange (or salmon) for ign killer

Grey to brown for tach signal

Yellow/black to grey to choke solenoid

 

[merc850]

The white wire from the box is for pre-76 motors with non-ADI ignition, just cut it short and tape off.

 

[Dentcrew]

Everyone who has helped me on this is awesome! Gonna wire up tomorrow and post results. Ordered a new Stator on here as well, as the other was shot ( rotten wires ). Ended up having this issue with the engine to control box plug/connector falling apart yesterday, and he stator arrived today. Got it installed, so hopefully with the advise I've received to get the wiring re-done, it will fire right up.

 

[Dentcrew]

Go the wires done, but still have an unconnected Brown/Blue Stripe wire from the control box harness and still will turn over but no spark. Any ideas?

 

[Dentcrew]

Maybe THIS is my issue? Looks like the switch is missing a wire! It grounded, but no wire coming in. Guess this would cause no spark?

 

[merc850]

No that's the switch to short the ignition momentarily if the motor hits something in the water and flies up (Mercury Switch in diagram). Also in the wiring diagram there's no Brown/Blue Stripe wire - you must have a different control, post a picture of it.

 

[Dentcrew]

Has the Kill Switch (Toggle) Throttle Tensioner, Elect Choke Option (Never Has Worked) and Fast Idle Lever. The Neutral Safety Switch has been bypassed (nothing but issues) and worked without issue.

 

[merc850]

Definitely a new control box, did you follow "Chris1956's" wiring method?

 

[Dentcrew]

I followed Chris1956 wiring, but was left over with the Tan (or Brown) with Blue Stripe left over from the control box. All the wires coming from the engne are hooked up. From what I've read, may be for a "Warning Horn" that doesn't apply to this motor?

 

[Dentcrew]

TAN / /BLUE STRIPE

Alternate Color Temperature Switch to Warning Horn

 

[Dentcrew]

Any idea which wire would control that Toggle Kill Switch? Working with a No Spark situation, and wondering if it's a culprit as other tests seem to be fine of the stator, rectifier. Still waiting on someone to chime in regarding if I should get any "Juice/Readings" on any of the 4 Trigger Wires when cranking, cause I get NADA.

 

[Dentcrew]

After checking that Tan with blue stripe wire, if it's grounded and the ignition is on, it constantly beeps at the control box. On live when the ignition is on. Is it possible that this could affect a No Spark?