Wiring info for safety switch. where to?

[Techno]

My engine won't start and I traced it to a wire from the safety switch. I don't know where the wire is supposed to go because it's a yellow wire someone added. The other side of the switch goes to ground.
The book shows a black/yellow wire going from the safety switch to the switch boxes, it also goes to the ignition switch. Should I hook this yellow safety switch wire to this post on the box? The boxes are tied together on this terminal.

Or where do I hook the safety switch yellow wire that completes a ground when closed, or maybe it opens it from ground. It's not hooked up now so I guess it completes the circuit to ground for the engine to run.
Thanksss.

[Delta]

Hey techno:
I'm not sure I understand what ya mean,cuz it seems really obvious and I know you that you are much better than I am in this area.This is not a dig.I'm just saying I probably don't understand the question!
I just checked my switch,and when it is is the up/on/run position,it is completing the circuit.I just ohmed it.The wiring diagram for my Merc shows the blk/yel wire going to both switch boxes,on the same respective terminal.Maybe that's why they are 'tied' there.Maybe the previous owner disconnected it for some bad reason,and/or maybe that yellow wire was added later,as a safety kill switch for the fuel pump.
Good luck,Delta

[Techno]

I have a safety switch with a yellow wire coming off of it. Where should it go? I know the blk/y goes to the boxes but should this non standard yellow go there?
The safety switch I'm referring to is the one that clips to your jacket. It's unhooked now (the yellow wire isn't hooked up) so the engine doesn't run just like if you didn't hook the lanyard up.

Does your safety switch have a blk/yell hooked up to it? I think this is where/what the yellow is for.

[Delta]

We are talking about the same switch.Mine has two terminals.(1) blk/y only one wire connected to it.It goes to the ignition/key switch.ANOTHER blk/y comes from the key switch,and goes back to the motor.Somewhere it splits into two,and they go to their respective terminals on the switch boxes.
(2) Three black wires:One to the key switch,one to the instruments,and one back to the motor.
It seem to me that the switch is just completing a ground when it is in the 'run' position,and the black wires will vary on year/set-up.I really think your yellow wire is for a fuel pump that someone added aftermarket.
Do you have an electric pump that is not standard? Later,Delta

[Delta]

Hey Techno:
I just reread your post.
You dont have ANY wires going from the kill switch to the switch boxes?Did it run before,like that?
My manual says that ALL V6(1976-1989) have the two blk/y wires going to the switch boxes.The switch boxes have for horizontal terminals in a row on top.The one on the far left shows a white/blk connecting the two boxes on the same respective terminal.The next terminal(2nd from left) shows a blk/y wire going to each respective terminal.That is how my book shows it,and I checked to verify that mine is wired that way.

[Techno]

I hooked the wire up to the boxes and it didn't start. then I saw a terminal with the bl/y wire on it that was blank, I hooked it up there, I'm sure this is where it was hooked up.
Now the problem is it still doesn't start. No kick or nothin.
As far as the switch I do have a fuel pump but that has a toggle switch on it.

[Delta]

Check the fuses on your motor.I had one blow one time,with the same results...nuthin.
You might think about running your fuel pump through the kill switch.When yer flying outta the boat,its hard to reach down and flick your toggle switch off.:D ;)

[Rickracer]

Most safety switches have normally open, and normally closed terminals. Naturally, the normally closed ones supply B+ to somewhere (probably the switchboxes), and the normally closed ones ground out the ignition to kill it. This is an either/or situation. If you have B+ to one side of the safety switch, then it should be a normally closed setup, with the switchboxes getting power through the safety switch. Check to see whether the one wire that was hooked up goes to ground or B+, and you should be able to figure it out.

[captcarb]

The black/yellow is the ignition kill circuit. It goes from the switch boxes to the ignition switch. When the ignition switch is off the black/yellow is grounded, shutting down the ignition. The kill switch goes from the black yellow to ground. It is normally open. When the lanyard is pulled, the switch closes and grounds the kill circuit, shutting down the ignition. If the kill switch is disconnected, it cannot ground the circuit and is not your problem. Jim

[Propster]

Techno,

I am with Captcarb. I connected Black/Yellow wire from the ignition switch to the kill switch, then to the ground on the back of the tach. The black/yellow wire also runs from the ignition switch to the switchboxes). When the kill switch activates, it just grounds the black/yellow wire and kills the motor.

Maybe there is a short to ground between your switch box and the ignition switch. Basically, if it black/yellow wire grounds, the engine will not run.

[Techno]

I'm at a total loss why this won't at least fire up. I did hook up the coils which I have 12. I might have used some bad ones, only need 6. Rather than chase this down all summer I'm bringing it to a mechanic and let them fine the problem. The boxes are new and the heads were milled injectors checked out. The ECU could be bad and so could the stator and trigger but they Ohmed out right. The coils sould be bad too. I might have wired the boxes up backwards, inner for outer but they were marked so thats doubtful.

Thanks for the help at least I didn't run it with out the safety switch.

[AlaskaStreamin]

Hey Techno,

Try unplugging the harness at the motor. This will take all the control box wiring out of the picture. You can cross the starter solonoid with a screw driver and it should fire.
This trick worked when my daughter dropped my key overboard years ago while fishing. Good luck!

[captcarb]

Does this motor have spark at any cylinder?