Fuel pump wiring

[J Lamb]

Need to wire up a control relay for my fuel pump for a Yamaha. Is there a way to wire it so it runs only when the engine is running? If not can I go through the kill switch for the power or ground to the relay coil? I'd like to have some kind of safety in place. Need wire colors to look for.

[stvhelm]

This is typical for a pump in the boat system. If your kill switch has a 3 wire connection which does both normally open and normally closed circuits you can use the extra normally closed wire to ground your fuel pump relay. And to have the pump turn on with the key you can activate the relay coil with the postive from the key switch.

[J Lamb]

Pump mounted in boat. Looks like only 2 wires to the kill switch, need glasses to see the diagram lol. I assume it's a ground. Trying to find where I can hook the wiring up without going to the control. Hoping someone has done it this way before that can give me an idea.

[stvhelm]

just replace the killswitch with a 3 wire switch and do it the way i explained. its the simplest way with the least amount of wiring. your engine uses a normally open circuit and the fuel pump uses the normally closed circuit. flip the switch and both will shut off.

[stvhelm]

there are several threads on this topic. try doing a search and look for the diagrams.

[pyro]

Here's one way to do it. The lug opposite of the kill wire is used to complete the ground to energize the relay in the "run" position. This sketch also shows a FUEL enable switch on the dash, if you have one.

Here, the relay enables +12 to one fuel pump wire, and the other is hooked to ground. You can also do it with the fuel pump connected to +12 on one side with a switched ground via the relay to turn it on/off.

[J Lamb]

Did a search, man what a stress on the brain. My kill switch is built in to the control box. Don't want to have to disassemble it but still wouldn't do any good since it grounds when pulled so that wouldn't work. But I got to thinking if I use another relay for the ground side of the pump relay and use the 87A terminal, open when energized, I can make it work that way. So by pulling the kill switch the second relay will energize and kill the ground to the pump relay. Clear as mud? Just have to use a double relay setup. For now I wired it to be on with the key. Will work on the safety setup in the future.

[captcarb]

That will work.

jim

[pyro]

You can't just start putting relay coils across the kill wire, it's tied to the switchbox, and you must not mess with its voltage outside of simply grounding it to shut off the motor. There's some significant voltage on that wire. :D

Jlamb, you didn't even read my post and see the simple diagram? THIS IS HOW TO DO IT.

Jeez, it takes less than 15 minutes, you'll need a soldering iron and a couple of screwdrivers. I took mine apart today to help answer this question, since I want to do the same dual kill setup anyway.

Unmount the control box. Remove the screws and back cover(s).

The switch housing is simply nested into a slot in the control box. It will slide right out without tools. Loosen the main ground screw and remove the kill switch's black wire connection. the other wire will likely be a bullet connector.

Now that the switch is out of the control box, you'll need to remove the plastic lanyard hood from the switch itself, it's pressed into the plastic. Two flat blade screwdrivers and some presistence will remove it. Swap it with a 3-lug switch, re-solder the wire leads, re-assemble and re-install. Easy! You'll have one new wire coming out of your control box, the switched ground connected to the relay coil.

Here's the diagram again, surely it was overlooked in my post above. :)

[pyro]

Further spelling it out:

1. Remove switch.

2. Remove pressed-on switch hood.

I already explained the rest. This is easy, and safe too. I'll be obtaining my new switch and installing it this week, along with my fuel pump relay in the rear.

[J Lamb]

I saw the diagram. This is a Yamaha not a Merc. The kill wire grounds to the cdi unit. Same place as the rev limiter. Not going to cut anything just use the kill wire to ground the second relay if it is pulled. In a little more detail the second relay will be powered off an ignition feed, ground to the pump goes on terminals 87A and 30 of the second relay, closed when not energized. the coil ground will go to the white wire of the cdi unit. Pull the kill switch second relay is energized and kills the ground to the pump relay. Kind of simple just a little more wiring. I didn't want to have to add any manual switches if not necessary.

[pyro]

Sorry, I missed the "Yamaha" part. The kill switch functions the same way though.

You saw the post, but you're missing the important details. You can't just tie a relay into the CDI kill wire. You'll have several hundred volts across the relay, and it will likely f*** with the ignition biasing.

Can't you swap out the kill switch like the Merc box? Look inside, see what the switch they use looks like. It's probably a common standard part like the others.

[pyro]

Ignoring what I said specific to the mechanics of swapping the switch, the highlighted area is the existing kill switch. The third lug on the new switch allows for a simple circuit to turn off the fuel pump relay when the lanyard is pulled, (completely independent of the ignition system!)

[J Lamb]

I'm not sure of the voltage part on the kill side since it is a direct ground when pulled. That is the principle I'm basing the relay setup on. By using a switched ground (kill switch) to energize the second relay. I may be mistaken but I don't see how any voltage could be involved since it's a direct ground. Really don't want to take the control box apart. Them japs have that harness packed in it pretty good:eek: . Besides I have to get the powerhead installed first so I can't really test it out yet. If I can scan the schematic I'll post it.

[pyro]

Direct ground to what? One side of the kill switch is grounded, the other side is connected to to a CDI wire that pulses up to several hundred volts while the engine is running. In other words, if you're thinking of tying a relay coil to it, and the other side to +12v, that won't work. Now you have a ??? ohm inductive load across a critical part of your motor's ignition. Won't work.

There is no simple way around this. Trust me. you don't need to post a schematic, because the part I highlighted in yellow is the only part of the scematic that applies here. One switch to ground. Take the box apart already, I'm getting cranky...

[stvhelm]

pyro's drawing is right on. I would just eliminate the fuel pump switch and get that 12v + from the ignition switch so it comes on when the key is turned on. keep it simple

[150aintenuff]

KISS.... on the Hot side of kill switch tap the IGN wire for relay to IGN purple... EASY.... Ground to ground... and your done...and if you want the fuel pump master switch on the constant hot from BAT source lust install the switch before the relay and switch the 12V constant as well.... lends you the ability to run the carbs dry for storage OR for diagnostics ect... how mine is.. turn on master switch pump initializeds and primes (on timed relay) and shuts off in 15 sec... turn on key relay re initializes.. fire motor and go...

PYRO MOVE THE FUEL PUMP MASTER SWITCHTO THE CONSTANT HOT LEAD..... allows for an anti theft as well that way.... even if they steel the keys... and get the ING lanyard.. an unmarked second fuel kill is instant anti theft...

[pyro]

what???

NOTHING should be tapped into the hot ignition side of the kill switch. NOTHING.

[J Lamb]

I would take that as a switched ignition source. Most people should know you don't tap into the switch itself. ONE MORE TIME. This is a YAMAHA. Wire colors mean nothing to me from a Merc standpoint. Principle is basically the same but there are differences. I already have the pump wired off a switched ignition source to power the relay. When I get the motor running I will verify voltage or not on the white kill wire and leave well enough alone if there is. I'm done.

[pyro]

Most marine wiring colors are standard, as far as I knew, with regard to critical functions, maybe I'm wrong. Whichever wire comes ON with the key on yours, (it will be connected to all the gauges, etc.) That's where the relay ties in. The other lug would go to the double-throw kill switch.

[150aintenuff]

kill switches are ment to KILL... they function best when everything engine ignition and fuel related are behind them....

battery-key switch... ign terminal on key switch... kill switch ... ign system and fuel system relays and ect..... all off... mags grounded... no fuel no spark.... better yet ... no crank either....


the way you have the master fuel switch in your diagram will not cut power from 12V+ if the relay shorts closed.... if the points weld themselves together with power on having the coil switched with a disconnect dont do ****.... the point of a relay is to remove the loads from the switched circuts on the dash back to battery power... AKA the fuse block... your fuel master switch in the diagram is on the WRONG circut.........

[150aintenuff]

Like this....


THIS WAY KILLS FUEL INDEPENDANTLY FROM COIL OPERATION!!!!!! INCASE OF RELAY STICKING ON AFTER YOU PULL KILL YOU STILL CUT POWER TO FUEL PUMP!!!!! I HAVE HAD THIS HAPPEN AND THIS IS THE ONLY WAY TO REMODY THAT FROM HAPPENING...

the FEED WIRE from the kill is 12V.. its goes to hundreds AT the switch box... not the kill switch.... NO terminals are ground... NC are 12V.... NOT GROUND... a kill switch OPENS power and Closes ground.... you CANNOT ground the pump TO the switch... GROUND LOOP CITY..... ALll accessory grounds should go to 1 central point and back to Batery via BATTERY CABLE in atleast 8 GA size for the newer high amperage charging sysytems... 40+ amps..

[stvhelm]

you know if you want to make it real easy just take a piece of string and tie one end around your ankle and the other end to the fuel pump wire:D;)

[150aintenuff]

I originally wired my pump like Pyros diagram... had a batch of relays that were flawed and 3 of them made their way into my boat... (luck of the draw I guess) and 2 were used as trim relays... the other was the fuel.... the boat spun due to the motor self trimming itself out of the water.... and the next week the pump stuck on even with everything off and pumped the engine full of fuel.... (needle seats couldnt handel the pressure for 24 hrs....) and once I realized that everything fuel related was running and ON I had a block full of fuel and a WHOLE LOTS OF DEAD GRASS below the boat... the relay bounced as I backed the boat into the yard to wash and arc'd itself in the ON possition and even though the coil was OFF the pump was on.... Now I kill power from batery AND the coil... and the switch for the fuel pump is dash mounted and unless you knew which one it was or that it wasnt just a blank switch the boat WILL NOT START!!! regardless of crank, spark, or any other means of running... Ive had people try to run it when I wasnt there and they never have sucessfully started the boat..

[BUSHWACKER]

KISS.... on the Hot side of kill switch tap the IGN wire for relay to IGN purple... EASY.... Ground to ground... and your done...and if you want the fuel pump master switch on the constant hot from BAT source lust install the switch before the relay and switch the 12V constant as well.... lends you the ability to run the carbs dry for storage OR for diagnostics ect... how mine is.. turn on master switch pump initializeds and primes (on timed relay) and shuts off in 15 sec... turn on key relay re initializes.. fire motor and go...

PYRO MOVE THE FUEL PUMP MASTER SWITCHTO THE CONSTANT HOT LEAD..... allows for an anti theft as well that way.... even if they steel the keys... and get the ING lanyard.. an unmarked second fuel kill is instant anti theft...
Just a thought, some may not know what "KISS" means, I'll yeild to the gentleman from Oregon rather than sayin :D

[pyro]

I like how Helmut posts "keep it simple", then Nick posts the KISS comment right below (keep it simple, stupid), then proceeds to thoroughly confuse everyone further with more ideas. Did anybody see the part where Helmut said I had it right?

By tonight, this thread will probably be on page three, and there will be about four more illegible, mislabeled diagrams showing other configurations that "also seem to work", along with more second grade english skills that nobody can understand either. Does anybody proofread anymore?

I ASSUMED that it would be understood that the +12 on the switch refers to key-on power at the dash, not constant battery power. My mistake, I should have labeled it better, sorry for the confusion.

I'm no poster child, mine was hooked up half-assed all of last summer, I'm just now getting around to doing it right.

THE ONLY THING THAT SHOULD BE HOOKED TO THE KILL WIRE IS THE KILL SWITCH ITSELF. Connecting the relay here is WRONG, regardless of whether it's a Merc or a Yamaha. If there was indeed a +12 source here suitable for switching relays, than it would be a direct short if the switch were to be pulled. OK, so there's an internal resistance in the switchbox that allows this +12 to be "pulled down" by the kill switch, causing a voltage drop across this said resistance. That being said, you don't hook up relay coils in series with a resistor. The relay coil should be seeing a direct +12, or nothing. No more of this gray area crap!! Please don't try to interpret this paragraph unless you actually understand ohm's law.

[pyro]

Here's a spaghetti sketch for those who are confused by schematic diagrams and ohm's law. This uses an ordinary automotive relay in the sketch, by the way. To add extra confusion (to fit the theme), I have reconfigured the relay to switch the ground connection instead of switching the +12v end of the business. I have also added the cut-off switch as Nick suggested (near the pump of course), along with the dash switch. I even added part labels. :D

EDIT: I posted the first sketch mostly as a joke, for those who don't understand symbols. As stated later in this thread, it isn't really a good idea to switch the ground return at the fuel pump.

I added the revised diagram here. The second image is the correct one. THIS WAY WORKS.

[Riverratt]

If I use one of the 4 terminal engine kill switches that have a pair of NO and Nc circuits could I run the purple wire through it since the key is right beside it or should I run the ground through it? Does it matter?

[pyro]

I'm not sure I understand the question. I'm not familiar with your switch, but if it's a true NO/NC switch, then you can use the other side of the switch in the same manner as described above. If the two sets of contacts are independent from each other on your switch (no common), than you can switch the +12 end of the relay instead of the -GND end instead, if you like. Doing it that way could eliminate the extra switched ground wire going up to the dash.

[Riverratt]

They are independent. I bought it from Rickracers a few years ago when I was going to run an electric fuel pump in my other boat. It is an aftermarket switch

[150aintenuff]

PERSONALLY the only difference in your wiring and mine pyro is you switch ground.... I switch power... thats it... and BTW a splice is in PARALELL NOT series..... the IGN still sees a constant 12V with no inductive load from the coil of the relay... also your assuming a yamaha kill switch is shorting ground.... ALOT of kill switches if NO/NC cut power and complete the ground.... breaking power in.. and then grounding the switch boxes..

[stvhelm]

Here's a spaghetti sketch for those who are confused by schematic diagrams and ohm's law. This uses an ordinary automotive relay in the sketch, by the way. To add extra confusion (to fit the theme), I have reconfigured the relay to switch the ground connection instead of switching the +12v end of the business. I have also added the cut-off switch as Nick suggested (near the pump of course), along with the dash switch. I even added part labels. :D

THIS WAY WORKS.

switching the pumps ground with the relay is not all that safe depending on where the pump is mounted. Its possible for the pump to turn on if its mounted to a metal surface or if something metal like an anchor chain touches the pump it could turn on unexpectedly. I saw a problem with this set up before when someone used reinforced braided fuel line. the pump just kept turning on an off for no reason. the braiding was just barely touching the pump and completeing the circuit.
I had it set it up in my stv for a while like this until i saw the potential problem on someone elses boat.

[pyro]

Good point. I was going to do mine with a switched +12v anyway. It makes more sense.

Nick, how much voltage drop appears at the kill wire if you place a relay coil across it? Have you actually checked? Just curious. Judging by your series/parallel comment, I'm under the impression that you had no idea what I was specifically referring to when I referred to "series resistance", so I'm going to explain it, based on the info that you supplied saying that the kill wire is at +12v while running.

If the switchbox blk/yel connection is at +12v, it's not tied directly to +12 of course, because grounding it would result in a shower of sparks. There must be an internal ballast resistor inside the switchbox, which by allowing the connection to be grounded through the kill switch, it causes a voltage drop across this internal resistance. Attaching a partial load (relay) to this connection would also cause some sort of voltage drop across this connection's internal resistor. The switchbox is expecting +12, or zero here, but nothing in between. A relay coil would yield a "gray" voltage value in the single digit range, depending on the ratio of relay coil ohms to internal switchbox ballast ohms.

If the ratio is bad enough, the relay might not even energize. Or it may disengage when battery voltage drops, (such as using trim), thus causing pump to cut in and out. Or, this half-pulled-down kill wire voltage may even cause the ignition system to cut in and out. This is why the kill wire should only OPEN, or GROUNDED. NOT pulled down by an indiscriminate resistive and/or inductive load.

If you wanted to use the kill wire as a fuel pump enabling trigger, you would need to build a small transistor amplifier circuit to turn on the relay, as to not significantly bias the voltage of the kill wire connection with a several-hundred-ohm load.

Now you've opened a can of worms. I didn't want to go all "hardcore nerd", but I'm left with no other choice. What ever happened to KISS? :D

If the kill switch is a 2-lug switch, replace it with a 3-lug switch and hook it up like my first diagram on page 1, (or with the mentioned NC/NO switch), as well as a safety cutoff switch at the pump. That's as Stupid Simple as it gets with safety still kept in mind.

I'm throwing out some hypothetical ideas here, someone please fill me in if I'm as clueless as some of you seem to think I am.

[j_martin]

As long as KISS went out the window, you could use a timer circuit (555) that powers the fuel pump for maybe 5 seconds, then requires that a pulse (from the tach maybe) be present to keep the relay closed. If the engine stops, the pump shuts off until the power is cycled. If a pulse is available at the kill switch then you could have instant shutdown of fuel before the engine spins down.

There might even be an automotive fuel pump module that does all that off the shelf. I suspect that all that function is built into the ECU.

hope it helps
John

[150aintenuff]

Pyro a 12V dc Relay coil will energize at 6V actually and with less than .25A draw at 6 V.... they dont consume very much power... they are designed that way..... I deal with WELDERS all day long and they use all different kinda of relays... 99% if the new stuff can do the switch on a Circut board with screen printed wire smaller than we can see.. its not rocket science... I will test the voltage drop across a 7 way 7 load relay that has a 12V dc
coil on it tonight (take your standard 4 prong auto relay and build 7 of them together...) i will garrantee its less than most standard inline connectors put on by novices...

as for a timer modual... Let me crawl under the dash and see if I have a PN on it..

the relays are VERY effieiient its not like your powering a 400 W stereo off a 12V line... maybe a total load of .5W if that.. the higher the resistance... IN PARELLE nothing in a boat should be series wired EVER.. if it is your WRONG!!!!

STV HELM... I see you see my methodology about ground switching.. IT SUCKS... to much risk of failure of the switch circut.... it is also called REVERSE polarity switching.... NOT GOOD IN A COROSION ENVIRONMENT... as when circut ground is open the power will ground to WATER, FUEL, METAL, any thing it can...... as 12V + will be running through everything in the circut... and if you ever take the time go from your negitive post on your batery with the - Lead on your METER and place the + lead in the water... YOU WILL GET A VOLTAGE READING!!!!! and if its ABOVE .200 V YOU ARE ERODING AWAY YOUR OWN PARTS THROUGH GROUND LOOP CAUSED COROSION!!!!!!


ALSO if you switch Ground and use AN fittings and a good Hose and your fuel sender has 12V + and a ground wire the GASOLINE can become the ground....... INSTANT FIRE HAZARD!!!!!!!!!!!!! or worse DEAD SHORT FROM 12V+ pump feed to ground......

[150aintenuff]

also for the fishermen on this site.... a voltage reeding above .215V repulses fish from your boat...... due to it effecting their nervous system through their latteral line...

[150aintenuff]

pyro.. ill go nerd for nerd any day with ya.... we are doing the same thing here... how many ignition only hot items are on your boat, or your car, the are all taking away from the ignition voltage.... and you dont see every DIS automobile failing when you turnup the radio now do ya....

when you wire 2 resistive loads in paraelle the total resistance of the circut STAYS THE SAME... the only circut loss on the original line is the connector TAP its self... NOTHING MORE... they are totally independant of eachother...

[pyro]

Oh boy..... You still don't have the slightest, faintest idea what I'm talking about, when I refer to series resistance and voltage drop in the switchbox. I'm not talking about the whole ignition system or the entire electrical system's voltage, I'm taking about the KILL WIRE'S voltage alone. Right over your head. (insert airplane flyover sound here)

THERE IS A SERIES RESISTOR inside each switchbox, inline with the kill connector lug. YOU CAN'T SEE IT. It's there. This has absolutely NOTHING to do with wiring, so stop the series/parallel wiring comments, because this is over your head.

I'll try to explain, one more time. The resistor is there so the kill wire voltage can be "pulled down" by a short to ground. This causes a full 12V drop across the internal resistor. The switchboxes see zero volts at the kill connection, so the motor shuts off.

When you hook up a relay coil to the yel/blk kill wire, YOU ARE PLACING A LOAD IN SERIES WITH THIS INTERNAL RESISTOR. This is the "series" I am referring to. The voltage drop occurs BECAUSE of this internal SERIES resistor placed inline with the kill connection. Measure the resistance (ohms) of the relay coil. If you measure the voltage drop at the blk/yel, mearure relay coil R, then back-calculate, and you'll actually be able to determine the value of the internal resistance in the boxes. If the internal resistance's value is equal or greater to the relay coil's resistance, then you will never see 6 volts across your relay coil, and the end result would be a kill wire pulled down below 12 volts, but not zero. Your relay is probably in the 100-500 ohm range. I would expect the internal R at the switchboxes to be greater.

REPEAT AFTER ME: "I will not hook extra bullsh** up to my kill wire."

You still don't believe me, OR understand me, do you?

Put your relay on the kill wire and measure the voltage. Try it! I'm sick of explaining this...

[pyro]

Keep in mind, I'm still saying all this assuming what you said about 12v at the kill wire is actually true, but I have little reason to believe it now. It seems more likely that there's a running pulse present there, possibly over a hundred volts, and nothing when it's not running. If that's the case, you can't run a relay from there anyway, and it's back to the correct method which has already been laid out.

Now I'm curious, I'll have to test my system this weekend to find out.

[pyro]

In case anyone else is going this route, I'll warn you ahead of time:
Murray's, Radio Shack, and True Value hardware doesn't carry the ON-ON SPDT 2-position metal-head toggle switch. All of their double-throw switches are ON-OFF-ON 3-position. I'll have to order mine through www.mouser.com or similar...

[j_martin]

http://stores.ebay.com/Hobby-Electronics-and-Accessories

[pyro]

Those are the low-end China-made switches. "Radio shack grade."
I'm looking for the best, not the cheapest, and it needs to have reasonably low actuation force like the stock switch.

This is probably what I need:
Mouser Part #: 691-2FB53-73/TABS
http://www.mouser.com/search/ProductDetail.aspx?R=2FB53-73%2fTABSvirtualkey69100000virtualkey691-2FB53-73%2fTABS
need to take measurements of the switch when I get home from work.

[pyro]

I checked my control box with a voltmeter today. There is ZERO volts, nothing, at the kill wire with the key on. As suspected, it only produces pulses there, like the tach wire, and this would NOT work as a relay trigger as Nick suggested. No priming with the key on, and the relay would simply chatter if you tried to connect it there.

Please take my word for it next time, so I don't feel the need to argue...

[1BadAction]

dude, haven't you learned? nick knows all about everything, duh.

[j_martin]

Pyro,
I thought you were looking for Shadio Rack switches.:D

[jphii]

Just wire it to the open end of a wrist pin:rolleyes:

[j_martin]

NO NO NO, the closed end!!!!

[PORT]

Are you guys using marine grade relays or just something from radio shack, automotive??

I am in the middle of wiring my twin Bridgeport electric fuel pumps and seen this thread and decided to do it right utilizing a relay connected to the N/C kill switch contact. (I was just going to tap ignition, but a lot of valid reasons about pumping fuel if motors off)
Thanks

[j_martin]

You better read the whole thread before you do any wiring. Believe me.

[pyro]

Are you guys using marine grade relays or just something from radio shack, automotive??

I am in the middle of wiring my twin Bridgeport electric fuel pumps and seen this thread and decided to do it right utilizing a relay connected to the N/C kill switch contact. (I was just going to tap ignition, but a lot of valid reasons about pumping fuel if motors off)
Thanks

This actually strted out as a Yamaha system question, but I guess I've hijacked it and chased the guy off now. oops. :rolleyes:

As stated earlier in the thread, some, if not many/most control boxes have a 2-lug kill switch that has to be swapped out for a similar 3-lug switch to accomplish this double-kill feature.

I'm going to use an ordinary automotive relay for mine (with 100% duty cycle rating), although it would be wise to use a good sealed marine-grade relay for saltwater applications.

[150aintenuff]

tell ya what pyro... ill fire the stream on the hose and tell ya how much voltage is on my kill circut... fctory merc controll with factory harness.......... I will bet its either 12V constant or 0 V constant.... not 100's

[150aintenuff]

I checked my control box with a voltmeter today. There is ZERO volts, nothing, at the kill wire with the key on. As suspected, it only produces pulses there, like the tach wire, and this would NOT work as a relay trigger as Nick suggested. No priming with the key on, and the relay would simply chatter if you tried to connect it there.

Please take my word for it next time, so I don't feel the need to argue...

KILL WIRE ONLY BLACK/ YELLOW doesnt even do the pulse.... its a secondary ground to shut off the input signal to the box.... kinda like the old brigs and stratton that used a metal lever to the spark plug top to shut off the coil... OPEN CIRCUT untill CLOSED NO PULSE NO VOLT DEAD!!!!!
the 12V PURPLE WIRE that is NORMALLY CLOSED ON THE SWITCH is the relay activation lead. DO NOT SWITCH GROUND IN A MARINE APLICATION!!!! you are floating on a ground......... and your boat is conductive if wet... bad idea..... in an automotive aplication the tires insulate you from the ground....


BTW pyro.... QUIT TRYING TO USE THE SWITCH TO GROUND FEED 12V+ to the relay coil

ALSO i deal with series resistance on a daily basis... and FYI i have an ociloscope i can place on the black/yellow if you want to show you that there isnt any pulse either...

[150aintenuff]

ociloscope readings.......


130-145 v sine wave on black-yellow wire terminal of switch box... at idle... grounding this lead to chasis shuts off primary mag ign circut...

[pyro]

Yes, that's what I tried to claim originally, that there was AC over a hundred volts, and you tried to say otherwise. so you're not going to hook up a relay there now? ha ha...

Nick, the whole point of the double-kill is to shut off the fuel pump when the kill switch is pulled. It's called saffety. Hook yours up however the hell you want, I don't care. You haven't suggested anything in this thread that actualy works, just throwing around fragments of mis-information.
1Bad summed it up. Never try to argue........

The MOUSER part 691-2FB53-73 is the closest thing I can find so far as a replacement 3-lug kill switch. Every dimension is the same as the original, except the "baton" is a little longer. Maybe use a shim here?


One more time, with EVERYTHING labeled. Can't possibly screw this one up.

[j_martin]

KISS

How 'bout putting in a double pole double throw kill switch. One side switches 12 volts from the ignition switch to the fuel pump when on. The other side shorts out the kill wire to ground when off.

hope it helps
John

[pyro]

That would work too, and it would eliminate the switched relay ground in favor of a switched +12v to the relay coil.

The only potential problem might be part clearance inside the control box. I'll check mine tonight, and see if the fat-bodied DPDT switch fits...

[tlwjkw]

Just a suggestion. Tha easiest way we found other than switchin' tha ground
was ta add another kill switch (just for tha 12+ power) next ta the motor kill switch (mine mounted in tha dash so I wouldn't forget ta use 'em) and splice tha two lanyard ends ta one cord. Tha extra one shut 12+ power to a multi pole relay goin' to tha fuel pumps, fuel sol. and nox sol. Whatcha think Pyro............Tdub

[Tom Foley]

Just a suggestion. Tha easiest way we found other than switchin' tha ground
was ta add another kill switch (just for tha 12+ power) next ta the motor kill switch (mine mounted in tha dash so I wouldn't forget ta use 'em) and splice tha two lanyard ends ta one cord. Tha extra one shut 12+ power to a multi pole relay goin' to tha fuel pumps, fuel sol. and nox sol. I think tough that if ya try ta do it with one switch ya gotta have something with one set of NO contacts and one set of NC contacts with a single throw since ya gotta make tha ground side and open tha 12+ side. Whatcha think Pyro............Tdub

Bingo ! Only why the relay on our stuff ? Just run 12 or 10 gauge wire with a 25 amp fuse through the secondary kill switch . The pump draws 13 amps I believe . No need for a relay , just a good Cole Herse switch .

[tlwjkw]

First I made an edit ta my post. We use tha relays cause we were controlin' multi items by a single function in case of a big wreck or malfunction of balls gettin' to big of which there is no problem of that anymore. I either got smarter or older. I'm pretty sure its tha later:D Plus ya can size tha wire and tha inline fuses ta whatever ya need ta operate and control it all with two little wires. ................Tdub

[pyro]

I found the correct switch at Grainger today for under $5.

Carling switch # 691-2FB53-73-TABS