Add a kill switch

[morelor]

I have a 1969 25hp Johnson Outboard that i’m trying to add a kill switch to. It has a keyed ignition switch that I believe is aftermarket and I want to add the kill switch to work in conjunction with the ignition switch but I have not been able to figure out how to wire it.

I have read on the internet that I should have a yellow kill switch wire but I looked everywhere and there is not one anywhere on the motor.

The model is 25R69D. Here are some pictures of the ignition switch wiring:

https://drive.google.com/folderview?id= … sp=sharing

[frankr]

Your ignition switch will have two terminals marked "M" (Or one "M" and one "GND"). At any rate those are the kill wires. Just extend them to the kill switch. No yellow/black wire on that system, so you can’t find one.

[morelor]

Thanks for the info Frank, I’ll take a look at the switch/wire tomorrow. I guess I should also mention that the ignition switch currently does not turn off the engine, it will only start it. I’m not sure if that means that the ignition switch is wired incorrectly.

[frankr]

OK, let me start over then. There should be two wires coming out from the magneto, below the flywheel. Those are the kill wires that are supposed to be going to the ignition switch as mentioned above.

[fleetwin]

Those wires are probably connected to the stop button on the engine now. You would have to cut the leads off the stop button, then connect them to the M terminals on the key switch. Why is it that you want to do this? As a theft deterrent? Seems like it would be easier to press the stop button then fumble with the key mounted on the side of the pan to shut the engine off.
The only reason I ask is because I hate to see you mess up the wiring on this nice old 25hp needlessly.
When you say "kill switch", are you referring to a safety lanyard stop switch that can be clipped to your belt? If so, I’m sure you can find a conventional stop switch with that feature and install it in the current stop button hole. Again, try not to mess up the original wiring. You can buy the actual terminals/plastic clips so the new switch could be wired nicely to the mag plate wiring.

[1946zephyr]

Any correct outboard starter switch will have the "kill" feature in it.
With an automotive type of switch, the on position will allow current to continue to the coil and the off position with break that continuation.
With an outboard switch, things are opposite
The on position will break the ground continuation and the off position will continue it. On the switch, the "M" terminal should have wires coming from the mags then running back to a ground on the motor,
The solenoids are quite different too.
One small terminal (on the battery side} is a hot and the other is a ground, whereas on the automotive solenoid, both small terminals are hot.

[morelor]

Thanks Frank, I’ll make sure those wires are going to the M terminals on the switch. Fleetwin, unfortunately whoever installed the ignition switch must have removed the factory kill switch as well so I wanted to put one back on. I’m guessing they didn’t completely know what they were doing since they removed the factory switch and apparently wired the ignition switch incorrectly.

I think I should be able to figure it out now, thanks for all the help.

[fleetwin]

Just one final word of advice. Make sure that only the ignition stop leads are connected to those M terminals on the key switch. Adding a ground lead to one of those M terminals will kill that cylinder and melt a coil. I’m guessing this will not be an issue for your engine though, usually just happens on dashboard mounted key switches when someone thinks the M terminals might make a good ground for 12V accessories such as lights/radio.

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