Ignition switch wiring help

[ChrisAF]

Hi Everyone. I have a 1969 Mercury 350 (35hp) with a MerControl control box. Its the control box with the ignition switch and a push to choke button on top.  It is apparent that the previous owner replaced the ignition switch and made some changes to the wiring. The OB will start and run by switching the key, however, it will not turn off when switching the key to the off position. Pressing the choke button is the only way to shut off the OB. Also note that the choke button does not actuate the choke.

With that said, I want to start fresh with a new ignition switch and wire it properly. Below is a schematic of the wiring. I believe I need a 6 terminal switch (non push to choke). Can someone link me to a suitable replacement?

Secondly, I need help making the connections. From the diagram, it was orginally labeled A, B, D, E, F,G. However, all new switches are labeled B I M M S C. Can someone tell me what color wires go where with this switch labeling?

 

• This topic was modified 1 year, 9 months ago by ChrisAF.

[ChrisAF]

I did some searching through other forums and someone refernced the part number 34198 for MerContronal ignition switches. Searching that number, i found this: https://www.crowleymarine.com/parts/11840.cfm

It seems to have the proper A B D E F G lettering for an exact match to my wiring schematic. Is this what I need?

 

[billw]

Sure looks like the right one to me! I’d be placing the order, if it were my project!

Long live American manufacturing!

[ChrisAF]

Following up on this, I have purchased the igntion switch above and I hope that this will return me to the stock configuration.

On a related note, I want to install a kill switch. As I understand it, the proper way to shutt off an OB with a  dual magneto setup like this is to ground both magnetos. With the current configuration, both wires from the magneto go to the choke button. With this configuration, the OB shuts off when the choke button is pressed. As I understand it, this connects both magnetos together. At any given time, one point will be open, and one point is closed and therefore one magneto grounded. Thus, connecting both magentos together under the current configuration essentially grounds both and shutts off the OB. Am I correct in understanding the current setup?

If so, then installing the correct switch will then isolate the wires to both magnetos. Therefore, I can install a kill switch such that it connects both magentos when triggered, thus connecting both to ground and shutting off the OB. Is that correct?

 

[billw]

That’s correct. When you turn your soon-to-be-correctly-wired key switch off, it should do the same thing, connecting the salmon and white wires together. For a kill switch, you just would wire it in parallel with those two wires on the key switch. Just be advised that there are different kill switches. One is normally open, and closes when pulled. That’s the one you want. The other is normally closed, and opens when pulled. That would be for a battery ignition system, like a stern drive.

Long live American manufacturing!

• This reply was modified 1 year, 9 months ago by billw.

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ChrisAF

[ChrisAF]

Thanks for confirming!! I have a kill switch already that allows for both configurations. I’ll be sure to wire it ao that it is normally open. I’ll follow up here once I get the new switch installed to confirm it works correctly. Hopefully this will be of help to someone else in the future.

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[ChrisAF]

Just following up to say that I was able to find the replacement switch on ebay (orginal part number is 34198, replacement part number is 54213). I connected it exactly according to the diagram attached in my original post and it works perfectly!

I also added a kill switch. One lead to the G terminal on the switch and the other to the E terminal, corresponding to salmon and white wires, respectively. It’s configured such that it is in the closed position when the lanyard is pulled, therefore connecting the magnetos and killing the engine.

Hope this helps someone else in the future!

[Author]

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