HELP! This ignition is driving me crazy!! (1990 Force 50hp and US Marine ignition)

[Thecuff]

Rebuilding a 1990 Force 50hp(model 507X90D). The block is US Marine and so are the controls and switch. I don't have a model for the controls or switch though. I can jump the motor from the solenoid so I know the motor runs...not well...but it runs. I'm trying to get the ignition put back together right now but I cannot figure out this wiring harness and switch. I cannot find a diagram or explanation anywhere. I have the Clymer manual but this package is not covered and nothing is even close to the color combination. Here is what I do know and what I have so far:

harness wires are:
yellow/black
black/yellow
yellow/red
blue/white
gray/black
green/white
tan - this is the overheat alarm. It has a connector at the end of the wire but I have nothing to hook it up to. I don't have the alarm for it. Does it need to be hooked up to start the motor with the ignition?

it's a 6 prong switch and they are labeled:
M,B,M,I,S,C

What I know so far is that the yellow/red is labeled start on the engine block tag. I have it hooked up to the S on the switch. The black/yellow is labeled stop and I hooked it up to one of the Ms. The yellow/black is labeled choke and I hooked it up the C, which is the center prong of the 6. That's as far as I made it. None of the other wires are labeled except for the tan wire, which I mentioned above. I don't even get a click or anything with the way the switch and harness is configured so I know I'm not even close. Can anyone please help?!?! Thanks is advance ya'll!

P.S. I didn't tear this motor off the boat it came from so everything I've done so far is from scratch. I have no clue what the wiring looked like when it was actually in a boat and operational. It's currently on a stand.

 

[Thecuff]

I forgot to mention that I do have the shift and throttle controls fully installed and they are working properly so it shouldn't be tripping the neutral safety switch. I did try bypassing that anyway and still nothing.

 

[SkiDad]

i would look for the original service manual on ebay. I got one recently and it has more info for my engine.

not sure if this pic helps or not but you can search google images and see what you can find - i put in "force 50 wiring" and this is one that came up: https://www.google.com/search?q=199...s%2F591666-89-force-50-wiring-diagram;564;423

 

[SkiDad]

also check the diagram on this thread: http://forums.iboats.com/forum/engi...one-cd-coil-pack-ok?t=560226&highlight=wiring

 

[Thecuff]

mitzy,
Thank you for the reply. I've been looking for the original service manual on ebay for some time and can't find one for that model. I have decent diagrams from the motor side, it's the ignition switch side that I'm having issues with and I can't find anything with this particular wiring harness color configuration.

 

[Jiggz]

The engine wiring diagram linked by Mitz "1988 'D'-99 50HP shows the wiring diagram for the ignition switch as sub component of the control box. Look closely on the wire colors and the ignition switch (sw) terminal designation with the appropriate wires that go into it. You probably need to save and print it so you can enlarge and make it more readable. Here's some of the wire colors and their designation:

Blu/wht and Grn/wht do not go to the ignition sw but rather they are for the trim control sw.

The ignition terminal switch is wired as follows

Yel/blk - "C" terminal (choke position)

Blk/yel - "M" terminal (there are two either or will be OK) - Off Position

Yel/red - "S" terminal (Start position)

Gry/blk - (?) the only grey I can see from the diagram is a wire for the tach input signal coming from the rectifier.

There are three more terminals without wire based from your wire list above. And these are supposed to be:

Blu/blk or blu - for the other "M" terminal (off position)

Red/purple or Red - for the "B" terminal (battery or hot wire) this wire is usually in series with the interlock switch and then to the starter solenoid

And the last wire should be the "I" terminal wire(s) which is for accessories ("On" position). The most common wires on this terminal is the overheat buzzer (red/blu color), dash board lights, voltmeter, tach, etc.

And here's an overview how the ignition switch works:
In "Off" position, the two M terminals are connected together thus shunting the CDM white wire to ground (blue/black or blue) shutting off the engine. In "On" position, the two "M" terminals are disconnected and the "I" terminal connects to "B" to energize accessories. In "Start" position, the "S" terminal connects to the "B" to energize the starter solenoid. And when pushed in, the "C" terminal connects to the "B" thus energizing the choke solenoid.

 

[roscoe]

I just looking in my factory manual, my seloc manual, and the Clymer manual.

Your wire colors do not appear in any of the diagrams, regardless of hp, or year.

I'm guessing someone cobbled a harness together.

Likely you will have to pick a wire and make sure both ends of it are connected to the correct terminal.

 

[Thecuff]

Thank you very much Jiggz and Roscoe. You were both absolutely right. It was a "cobbled together" harness and Jiggz your description of the wiring was spot on. I should have taken a deeper look but I just wanted to thank you both. The blue/white and green/white wires were capped off and shoved back under the motor housing and not connected at the junction from the motor to the harness. I simply uncapped them, hooked up the green/white to the positive feed and the blue white to the "stop." Then followed Jiggz directions on where those should be connected at the switch. I didn't have a fuel cell hooked up to the motor, or my muffs, but she turns over using the key switch now. I'll let you guys know if I have any trouble turning it off once I actually fire it up and run it with water through the engine. I don't anticipate having any issues. Still a long way to go but it feels good to figure this piece out as it's been giving me fits! Thanks again guys! Big help!

 

[roscoe]

Great, now on to the next step.