Kill switch and lanyard.

[f_inscreenname]

Bought these two kill switches and lanyards for the race boat on eBay the other day and I?m having a bit of an issue with them.
In past installs of these things I would put them inline between the power from the key and the coil. Pull the lanyard and the power would cut off killing the motor (like turning the key off).
These new ones, you pull the lanyard off the switch and power flows through them. Put the lanyard on and the power is cut off. So I email the guy and he says, ?The wire is connected to your tachometer wire from - side of the coil and to ground. This shorts the coil and kills the engine. The engine will not start without the clip in place.?
Does this sound right? I?ve never done that before and would rather not chase electrical issues after I install the motors.

 

[rodbolt]

Re: Kill switch and lanyard.

NO NO NO
DO NOT short the tach circuit, most inboard and sterndrive gas tach circuits are either 12V from the key switch or a 5 V digital signal from the ECU. short circuiting them can lead to blown fuses or ECU's.
simply buy the correct switchs that are closed with the lanyard installed and opened with the lanyard removed.
most after market switchs can be wired either way.
not knowing what ign system your running thats all I can say.
yes it will kill your engine however it may kill other parts as well.
you would not hook a jumper from the coil primary to the engine block with the key on would you?

 

[f_inscreenname]

Re: Kill switch and lanyard.

That's what I was thinking R/B. To me it would be like grounding a hot wire and that would turn it into a very hot wire. Like a arc welding wire. Ya it may stop the motor but then burn the boat to the waterline. Also I am running a MSD box and don't think it would like it very much.
What would this type kill switch be used for?

 

[rodbolt]

Re: Kill switch and lanyard.

typically that switch was used for point type and most ADI ign systems on outboards.
typically you either ground the points on a magneto ign or ground the capacitor output from a power pack(cdi,switchbox) on alternator driven systems.
on most inboard and sterndrive gas stuff you shut off primary ign current by opening the circuit.
this takes away ign power and shuts down electric fuel pumps.
but there again I have no clue what type of ign system your running.

 

[f_inscreenname]

Re: Kill switch and lanyard.

Ignition system - Blaster coils, MSD boxes and a magnetic pick up distributors.

Now I see what they are used for. You are right and they will not work.
At this point it would be a shame after 42 years to burn this because of a wiring issue.

 

[rodbolt]

Re: Kill switch and lanyard.

I definatly would not short the ign system on that engine.
good looking nova though.
I put a 496 mag HO in a 26 nova with a bravo II.
boat taps 60 MPH anytime you wish.
but at 30 MPH its sipping fuel and quiet enough everyone can speak.

 

[f_inscreenname]

Re: Kill switch and lanyard.

Really? 60mph gives me good hope for it.
It is the original 1968 race boat with twin 454 (not original), one in front and one in back, to a single V drive and single prop. I would be very happy with 60.
I'm thinking "sipping fuel" is not an option with this one at any speed.

 

[cr2k]

Re: Kill switch and lanyard.

The one that breaks the circuit is for inboards/battery ign. (cuts ign power)

The one that makes the circuit is for outboards/magneto (grounds mag wire).