how do i kill fuel pump with factory mercury lanyard?

[hst714]

im trying to figure out the right way to kill my fuel pump with the factory mercury lanyard... it is a 1994 260, my fuel pump is a bosch. It (the fuel pump) is in the front of the cowl. when i pull my lanyard while the motor is running it kills the ign. but the fuel pump keeps singing. i was wondering how i could kill the pump with the factory lanyard or if its even possible?

thanks for any time/input, i appreciate it...

Matt

[flabum1017]

216858get a double pole, single throw six lug switch of the same style as what's in there, wire the kill wires on one side and the pump wires on the other. The kill circuit needs to be open when the lanyard is in place and the pump circuit must be closed.

[mach351]

I need to do mine also - I am going to use a standard 5 pole relay and kill the ground to the pump - just have to run one wire up to the switch and ground it from there.

[squirt gun]

matt i use 2 kill switches 1 for the ignition and 1 for the pump than tir the 2 lanyards together

[Bruster]

That's to easy.


216858get a double pole, single throw six lug switch of the same style as what's in there, wire the kill wires on one side and the pump wires on the other. The kill circuit needs to be open when the lanyard is in place and the pump circuit must be closed.

[hst714]

thanks!

216858get a double pole, single throw six lug switch of the same style as what's in there, wire the kill wires on one side and the pump wires on the other. The kill circuit needs to be open when the lanyard is in place and the pump circuit must be closed.

[sschefer]

The correct answer is to use a normally (no voltage present) closed relay. When the lanyard is removed the relay circuit becomes complete and the relay will be energized. This will open the circuit to the fuel pump and it will stop.

Be sure to wire the relay power throgh the ignition switch so that the power will be off when the key is off.

Wiring the pump through a separate toggle switch defeats what I think you're trying to do.

[flabum1017]

The correct answer is to use a normally (no voltage present) closed relay. When the lanyard is removed the relay circuit becomes complete and the relay will be energized. This will open the circuit to the fuel pump and it will stop.

Be sure to wire the relay power throgh the ignition switch so that the power will be off when the key is off.

Wiring the pump through a separate toggle switch defeats what I think you're trying to do.

I don;t like adding extra electrical crap, especially relays, a simple dpst switch is the most reliable. A CH switch is rated at 20 amps and can easily handle a fuel pump.....

[Forkin' Crazy]

That is not adding extra stuff. You can take away the ground on a bosh relay (which it should have to begin with) and it will disable it. Some kill switches already have three wires. Ground, Normally Open and a Normally Closed. Run the NC from the switch to the ground of the relay and the NO to the kill wire on the engine. Simple as that. ;)


I don;t like adding extra electrical crap, especially relays, a simple dpst switch is the most reliable. A CH switch is rated at 20 amps and can easily handle a fuel pump.....

[mach351]

I agree - I have horrible luck running anything but grounds through toggles - maybe it's the salt air around here, but toggles just don't last if they have any kind of amps goin through them. Relays seem to work best IMO.

[Bruster]

Normally an electric fuel pump is already switched thru the ignition switch to a relay and I assumed this is what was implied. On an I/O or inboard the fuel pump power supply is often wired thru the D+ alternator terminal, providing supply power for the pump only when the alternator is turning. There is still a relay involved.

.
The correct answer is to use a normally (no voltage present) closed relay. When the lanyard is removed the relay circuit becomes complete and the relay will be energized. This will open the circuit to the fuel pump and it will stop.

Be sure to wire the relay power throgh the ignition switch so that the power will be off when the key is off.

Wiring the pump through a separate toggle switch defeats what I think you're trying to do.

[Noah Burns]

Sorry to resurrect such an old post but my question is, when the lanyard is pulled (in the event of a crash) is the expectation that the switch will stop in the middle in the "off" position or move down to the second "on" position?

One being normally open, the other being normally closed and the off in the middle confuses me.

Sorry for the novice question but electricity sometimes gets me backwards.

[vnemous]

no middle that I am aware of. Either on or off. Might have 4 pole to kill engine and fuel pump or just two pole to kill motor.

[tlwjkw]

almost all tha after market "replacement" kill switches are 2 pole single throw... one normally open set of contacts (motor kill) and one normally close set of contacts (fuel pump/relay).... think there is an oem switch like this also....

they will have either 4 wires and/or 4 male sta-con connections... 2 "sets" of contacts.. like said "no in between or middle position" for switch... its either up/down, on/off, in/out.. what ever ya wanna call it....