1978 Mercury 1150 (serial 5052778) kill switch retrofit help

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Slimmdaddy

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I just upgraded from Jon Boats to my first bass boat (1978 Cobra Phantom with 78 1150), YEA ME!
I am disabled and am now on a mission to install a kill switch on this old engine. I purchased a quicksilver kit # 87 19674A07. In the RUN position the two wires do not make a circuit. In the OFF position they do. I am assuming that this style switch is used for magneto type ignitions and I have a distributor and coil.

My questions are:
1) do I need to incorporate a relay in order to kill the 12v from my key switch?

2) where might I obtain a manual that shows the wiring for this old beast?

I am very good with electrical and have no concerns about doing the job properly, just wanna make sure that is my one legged butt leaves the vehicle I don't have to then worry about catching the boat or being ran over by it.

Thanks

Slimm
 

gm280

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Re: 1978 Mercury 1150 (serial 5052778) kill switch retrofit help

I just upgraded from Jon Boats to my first bass boat (1978 Cobra Phantom with 78 1150), YEA ME!
I am disabled and am now on a mission to install a kill switch on this old engine. I purchased a quicksilver kit # 87 19674A07. In the RUN position the two wires do not make a circuit. In the OFF position they do. I am assuming that this style switch is used for magneto type ignitions and I have a distributor and coil.

My questions are:
1) do I need to incorporate a relay in order to kill the 12v from my key switch?

2) where might I obtain a manual that shows the wiring for this old beast?

I am very good with electrical and have no concerns about doing the job properly, just wanna make sure that is my one legged butt leaves the vehicle I don't have to then worry about catching the boat or being ran over by it.

Thanks

Slimm

Yes that is correct for most kill switches. When the switch is working correctly the circuit will be open, and if you should fall overboard or out of the driver’s seat, the switch shorts. And that is used in most point type ignition systems but can also be used to short out an ignition module also. It depends on how you wire it and to what. Not knowing your engine setup, you have to decide where the wires would shut down the ignition when the kill switch lanyard is removed... So as you stated that you know electronics, you should have no problem figuring how to wire that kill switch up to your ignition system to kill spark when the lanyard pulled out...
 

Slimmdaddy

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Re: 1978 Mercury 1150 (serial 5052778) kill switch retrofit help

Thank you for your reply, I appreciate your time. I am very comfortable with electronics and once I know what wire to either interrupt or short I will get it done. My problem is I don't know on this engine which I should do and I surely don't want to just start shorting out ignition wires.

Someone has previously been into the harness from the control box to the engine and replaced all the wires with either blue or red wires. It works but I don't dare start guessing. I found a diagram if the wiring and I will attempt to attach it. If the attachment works you will notice that I have added a pink and red arrow and a blue arrow to two wires which I think will do the job by either shorting the blue to ground or interrupting the pink arrow using a relay. If someone could just nudge me in the right direction I would appreciate it, I just don't want to start making changes and burn something up that I cannot afford to repair or replace senselessly.


Thank you
Slimm

50.jpg





Yes that is correct for most kill switches. When the switch is working correctly the circuit will be open, and if you should fall overboard or out of the driver?s seat, the switch shorts. And that is used in most point type ignition systems but can also be used to short out an ignition module also. It depends on how you wire it and to what. Not knowing your engine setup, you have to decide where the wires would shut down the ignition when the kill switch lanyard is removed... So as you stated that you know electronics, you should have no problem figuring how to wire that kill switch up to your ignition system to kill spark when the lanyard pulled out...
 

Quad82

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Re: 1978 Mercury 1150 (serial 5052778) kill switch retrofit help

I have the same motor and installed a Mercury brand kill switch to it. I ran my kill wires back to the motor and connected to the "mercury" switch located on the port side of the motor. Just wire it in parelal (sp) to the flip-over switch that is already there. It wires to the top lug on the switchbox and to ground.
 

Quad82

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Re: 1978 Mercury 1150 (serial 5052778) kill switch retrofit help

I have the same motor and installed a Mercury brand kill switch to it. I ran my kill wires back to the motor and connected to the "mercury" switch located on the port side of the motor. Just wire it in parelal (sp) to the flip-over switch that is already there. It wires to the top lug on the switchbox and to ground.

Made a mistake. I used 1 side to ground just above the titlt switch. The other lead went to the bottom lug on the switchbox. The same 2 locations as the orginal tilt switch wires to.
 

Slimmdaddy

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Re: 1978 Mercury 1150 (serial 5052778) kill switch retrofit help

Made a mistake. I used 1 side to ground just above the titlt switch. The other lead went to the bottom lug on the switchbox. The same 2 locations as the orginal tilt switch wires to.

Thank you Quad82 for your response. My engine does not have the little mercury switch that you are referring to, actually neither does the 1500 I just bought. I did however get my kill switch installed and wired, I just got my nerve up and broke the connection to the white wire I have noted in the picture I attached earlier with the red and pink arrow. I made my connection in the harness near the control box and used a SPDT relay to open that circuit in the event the kill switch is activated. I have been quite busy lately and apologize for not updating this post sooner.

On a brighter note I just picked up another boat with a 1500 on it that will be put on my boat. This new boat was a one owner boat, old fellow bought the boat new in 1977 and kept it in the car port when not on the water. He did use it a lot but took very good care of it and I am extremely pleased with the price I paid for the boat engine and trailer ($250). The old guy just passed and his son was left the boat but had no use or desire to be a boat owner and called me and asked me to come get it out of his way...

I wish you a great and safe weekend and happy boating!


Slimm
 

Chris1956

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Re: 1978 Mercury 1150 (serial 5052778) kill switch retrofit help

Slimm, Actually on those battery powered distributor motors, you can interrupt the white wire power to the switchbox, or ground the ornage wire on the switchbox, to kill spark. Either way will work.
 

Slimmdaddy

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Re: 1978 Mercury 1150 (serial 5052778) kill switch retrofit help

Slimm, Actually on those battery powered distributor motors, you can interrupt the white wire power to the switchbox, or ground the ornage wire on the switchbox, to kill spark. Either way will work.


Thanks Chris, that is great to know.
 

bestman53

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i know these posts are a few years old, but im having the same issue on my 1978-79 mercury inline6 115hp. i upgraded my 7-pin remote harness to a newer 8-pin remote. it has a kill switch on the remote but im not sure how to integrate it to my engine. im not getting spark so i think its the kill switch causing the issue.
 

Chris1956

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Your motor has a distributor, right?

If so, I do not think the kill wire at the engine is pulled through to the remote control. If you are not getting spark, check to see that there is voltage on the red terminal on the Switchbox, as well as the adjacent white terminal, when the ign switch is on.
 
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