Kill switch question

[jklnhyde]

I want to install a kill switch, but I'm confused about the terminal arrangement at the back of the switch. It has 4 terminals in a 'cross' arrangement; two across each other are marked 'M', the other two are marked 'C'. The instructions informme the C is Coil and the M is Magneto, but that's all the instructions say!
I found that 12v applied to either C or M will not flow to it's double unless the 'key' is removed. This sounds totally reversed to me!
Please explain what I'm trying to accomplish here...
It's for a Mercruiser 5.0L.

Rick

 

[pvanv]

Re: Kill switch question

It's a grounding switch. In other words, you ground out the mag and or coil when you activate the kill. So you need a ground wire to the switch.

 

[noah4009]

Re: Kill switch question

It's a grounding switch. In other words, you ground out the mag and or coil when you activate the kill. So you need a ground wire to the switch.

I have a 1971 55HP Chrysler. I just purchased the same switch. So are you saying that the ground wire that comes from motor and goes to the ignition should got to c first then other c goes to ignition switch? My igniton witch has 6 terminals. M, I, M, S, C, B. 1st m empty, I blue, M white, tach, S, yellow, starting circuit, C, green choke, B, red battery circuit. I see no ground to switch.

 

[pvanv]

Re: Kill switch question

The method of stopping a magneto-fired OB is by grounding the mag. So shorting the mag line to ground stops the ignition.

You may want to get a service manual to decode the wiring.

 

[Moody Blue]

Re: Kill switch question

Careful how you use that kill switch.

Not all ignition systems are disabled by grounding. Some of the older outboard systems rely on +12V to the switchbox to operate. In these cases, the kill switch is used to interrupt the +12V supply to the ignition system.

Basically that switch you described can be used as both a NORMALLY CLOSED (NC) and NORMALLY OPEN (NO) switch. I can't recall if the Magneto or Coil connection is NC or NO.

Someone should be along with a definitive answer.

 

[Silvertip]

Re: Kill switch question

Magneto systems require an open circuit to run and they short the magneto to ground to kill the engine. I/O engines use auto based power plants with a coil ignition system. In this application the coil needs 12 volts to operate so the switch is open to kill the engine and closed to run. The switch you have should also have a push to choke function for your outboard. If you are confused about the terminals, use an ohm meter across the two pairs of terminals. One pair will be open in the off position on ON in the RUN position. That set is for a coil ignition. The other pair will be closed in the OFF position and open in the RUN position. Those terminals are for a magneto system. For your application you should be using the two "M" terminals. If the switch does not have a push to choke function, you have the wrong switch unless there is a separate choke button located somewhere else on the console.

 

[jklnhyde]

Re: Kill switch question

Let me get this staright. I should install the switch within the ignition sytem wiring, to a wire that carries voltage and keeps the engine runniing.
Are we talking the starting system or the igniton system?
Since this switch works like a neutral switch on a shifter, then the coil 12v lead or the fuel pump 12v lead are great candidate.
What about the neutral switch lead itself?

My confusion is with the way the kill switch is operating. With the 'key' in place, 12v will not flow from paired terminals! It should be the other way around!!

Rick

 

[pvanv]

Re: Kill switch question

Hyde,

Your (5L inboard) arrangement is automotive-style. You will want to open-circuit the IGN wire when you activate the kill. It mimics turning the ignition switch off. So your switch will be wired Closed (short) when running, then trip Open when you pull the clip.

BUT, Noah,

Your (early-style 55 hp OB) setup is magneto. You need to Ground the mag to stop the motor. So your switch will be Open when running, then trip Closed (short to Gnd) when you pull the clip.

Two completely different applications. If this information is beyond what you understand, you may want to confer with a local marine electrician, rather than cook anything.

 

[noah4009]

Re: Kill switch question

Hyde,

Your (5L inboard) arrangement is automotive-style. You will want to open-circuit the IGN wire when you activate the kill. It mimics turning the ignition switch off. So your switch will be wired Closed (short) when running, then trip Open when you pull the clip.

BUT, Noah,

Your (early-style 55 hp OB) setup is magneto. You need to Ground the mag to stop the motor. So your switch will be Open when running, then trip Closed (short to Gnd) when you pull the clip.

Two completely different applications. If this information is beyond what you understand, you may want to confer with a local marine electrician, rather than cook anything.

I have a 1971 55HP Chrysler. It is not magneto, it is coil, alternator standard ignition. So what wire should I cut into going to ignition. Ground? hot?

 

[pvanv]

Re: Kill switch question

I believe you are mistaken. While the old Chrysler does have ignition coils, I believe you will find that they are fed by stator coils under the flywheel. That comprises a magneto setup. The alternator has nothing to do with the ignition -- just for recharging the battery, and is typically an extra coil under the flywheel.

On these motors, you can actually disconnect the battery, and the motor continues to run. Though that would be bad for the rectifier diodes, and isn't recommended -- could end up without a working charging system.

If so, grounding the lead from the stator coil is how the ignition is killed. Look at and test your current ignition switch. If it has M terminals (many aftermarket ignition switches will be marked that way), these are the ones that short to ground when shutting down.

 

[Silvertip]

Re: Kill switch question

Noah -- until you understand the differences between magneto and battery ignition systems DO NOT cut any wires. We can tell you don't understand this so until you do, don't screw up your wiring. Forget the alternator as it has nothing to do with your ignition.

 

[noah4009]

Re: Kill switch question

HI, I am sure you know better then I do. Well I have 2 coils on side, Under flywheel are 2 sets of points and 2 condensers, which are on the breaker plate.. When I got my wiring manual it shows 4 pictures of ignition/wiring systems. Magneto igniton, not mine, this has no breaker plate in diagram. Battery ignition-alternator 3 phase, this looks just like mine, Magnapower, here I do not see and condensers. this is not mine, and battery igniton alternator, this also looks like mine. The only difference between the 2 that I say are mine is the rectifier has 5 instead of 4 wires on it. HellllllllllllllllllP

 

[Silvertip]

Re: Kill switch question

Condensers and breaker plates also have nothing to do with whether or not you have a battery or magneto ignition. Ignition points and breaker plates were used before CDI units were available. So that's one more thing you can eliminate. If the diagram says Battery Ignition-Alternator, it is very likely this is a battery ignition system which requires +12 volts to operate and in that case the +12 volt feed to the CDI box needs to be open to kill the engine and closed to run the engine. If you have a magneto ignition the stator feed to the ignition box needs to be grounded to kill the engine open to run. Why don't you post your issue in the CHRYSLER forum. Lastly, very early on you were advised to check the back of the ignition switch for two "M" terminals. This indicates you have a magneto system and if you disconnect those two wires and measure across the switch, you should see continuity with the switch OFF and infinity (open circuit) with the switch ON. If it doesn't work this way, you have a battery ignition. There would then be an "I" terminal on the switch which is the +12 volt feed to the ignition box. With the key ON there should be +12 Volts on that terminal and with the key OFF it should show 0 Volts.

 

[noah4009]

Re: Kill switch question

Condensers and breaker plates also have nothing to do with whether or not you have a battery or magneto ignition. Ignition points and breaker plates were used before CDI units were available. So that's one more thing you can eliminate. If the diagram says Battery Ignition-Alternator, it is very likely this is a battery ignition system which requires +12 volts to operate and in that case the +12 volt feed to the CDI box needs to be open to kill the engine and closed to run the engine. If you have a magneto ignition the stator feed to the ignition box needs to be grounded to kill the engine open to run. Why don't you post your issue in the CHRYSLER forum. Lastly, very early on you were advised to check the back of the ignition switch for two "M" terminals. This indicates you have a magneto system and if you disconnect those two wires and measure across the switch, you should see continuity with the switch OFF and infinity (open circuit) with the switch ON. If it doesn't work this way, you have a battery ignition. There would then be an "I" terminal on the switch which is the +12 volt feed to the ignition box. With the key ON there should be +12 Volts on that terminal and with the key OFF it should show 0 Volts.

I am so sorry if I am in the wrong forum. I just was reading in here and saw a thread on kill switches. Just thought being I had the same problem or question I could ask here. I did not creat this thread. Anyway, On my igniton there's 2 M terminals. 1 is not used and the other has a white wire to it for tach, Then there is an I terminal, which the blue wire goes to, this goes to coil. Then S, which a yellow wire, for starter sircuit. Then a C for choke, Then a B, for red wire, battery.

 

[Silvertip]

Re: Kill switch question

You have a universal ignition switch and since the two M terminals are not used but the I (ignition) terminal is used, that says you have a battery ignition system. The I terminal should have 12 volts on it when the key is ON. To add the kill switch you connect it in series with the wire on the I terminal. Use the terminals on the kill switch that are closed when the lanyard clip is installed on the kill switch. Theredfore the engine will die if the key is turned off OR the lanyard is pulled.

 

[noah4009]

Re: Kill switch question

You have a universal ignition switch and since the two M terminals are not used but the I (ignition) terminal is used, that says you have a battery ignition system. The I terminal should have 12 volts on it when the key is ON. To add the kill switch you connect it in series with the wire on the I terminal. Use the terminals on the kill switch that are closed when the lanyard clip is installed on the kill switch. Theredfore the engine will die if the key is turned off OR the lanyard is pulled.

Thank You very much, Silvertip.