install a carter electric fuel pump question??

[old ugly]

my huckster project has a rotted out fuel tank. unrepairable.
i am mounting a tank under the seat and am going to run a 6v low pressure carter fuel pump with a pressure regulator. i would like to power the pump from the ignition switch BUT...
here is the question.

the power at the ignition switch on a model A runs through the ignition coil first then to the ignition switch. it seams to me that when the points are close the power is grounded out and the pump will stall. i tested with a test light and when the points open again i have power to the pump.
what are your ideas on a solution to this?
-rewire the coil so it is live only when the switch is on? or ?????

thnks
OU

[ModelA29]

I'd wire direct from the hot side in the terminal block and hide a switch under the dash.

[Bruce of MN]

With a fuse!

[nkaminar]

Since you are not building a perfect 100 point car, I would use a modern ignition switch and wire the ignition and fuel pump to come on when the ignition is on. Going through the coil the current will be limited and not draw down the voltage so that the fuel pump will continue to operate.

[Richard Knight]

However you wire your pump include a separate switch as a safety measure that will allow you to turn off the pump independent of the ignition. It can be in the circuit so that the pump comes on with the ignition but can be switched off in an emergency like a flooding carburetor.

[old ugly]

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thanks guys.
i think the best idea is to use all your suggestions.

-fuse the system (already wired in).
-redirect the original style wiring harness to a simple on/off ignition switch first. (and not through the coil but after the amp gauge).
-a separate (2nd) switch with a warning light.
-a fuel shut off valve somewhere in the line. (most likely just before the carb so it is easy to get to) for me i think this will be easy to remember to shut off as it is habit on the other cars.

if any more ideas please let me know.

haha. i thought the wiring was going to be simple until i realized the power in problem.

thank you.
OU

[stevemclark]

You can get an ignition switch with an ACC. lug on it. From Bert's : .https://modelastore.com/ignition-key...roduct_id=4144

[Y-Blockhead]

I rewired my Town Sedan so the ignition switch is before the coil. Then you can wire the fuel pump to come on with the ignition without interupting the coil. I added a relay to mine just to ensure enough voltage to the fuel pump. My car is 12v negative ground but I changed the "Modified" drawing to reflect 6v positive ground.

[nkaminar]

My fuel pump will not allow fuel to flow when switched off, even if gravity is in play. You should test your fuel pump to see if it will shut off the fuel when not on. Open a low point in the fuel line and install a piece of tubing if necessary to get the outlet below the level in the tank then turn off the pump to see if gasoline still flows.

[old ugly]

Originally Posted by nkaminar

My fuel pump will not allow fuel to flow when switched off, even if gravity is in play. You should test your fuel pump to see if it will shut off the fuel when not on. Open a low point in the fuel line and install a piece of tubing if necessary to get the outlet below the level in the tank then turn off the pump to see if gasoline still flows.

that is a good idea. I'll check that.

the fuel shut off I'm installing near the carb will stop the fuel as long as i always remember to shut it off. (sometime old people forget stuff).

all good stuff here
thank you
OU

[desotoguy]

Might want to look at this for a fuel pump controller. https://www.revolutionelectronics.co...Fuel_Pump.html

[fast150]

I’m running a Weber 2 barrel carb. I use a low pressure, 2 to 4 psi fuel pump wired using the Revolution Electronics controller. I’m not using a pressure regulator. It works great and takes the worry away from having to use a separate switch to get power to the pump.

[old ugly]

i am looking into that controller and if they will ship to me in the frozen north.

waiting on the fuel pressure regulator, then i can see if it will go low enough for the model A carb.

thank you
OU

[old ugly]

well buying the controller is out of the question. they won,t ship to canada.

OU

[Y-Blockhead]

If you are concerned about the fuel shuting off in an emergency, I used an inertia switch from just about any older Ford product in my '55 Ranchwagon.

Similar to this one; https://www.ebay.com/itm/23524530097...Bk9SR7jYuersZQ

[old ugly]

i may have an issue with too much pressure even with the regulator, (still working on that) no being very successful.
BUT
i have a question on a different route. i have worked on lots of cars with vacuum fuel pumps, they pump to an elevated location, usually mounted on the cowl then gravity to the carb.
i may check to see if i can find an original one, the problem is they are all almost 100 years old now and most are probably not functional. the last one i did was bad inside and took a lot of fix.n to get it back working.
is there such a thing as a more modern vacuum fuel pump that is used these days?
thank you
OU

[katy]

Originally Posted by old ugly

Is there such a thing as a more modern vacuum fuel pump that is used these days? thank you

An online search shows them.

I remember (back in the '50s) lots of problems w/those "vacuum pumps".

[old ugly]

Here is the solution.
There is so little psi at the model a carb which was originally being supplied fuel via gravity that this fuel pump and regulator set up on a remote tank can not be set low enough. The pressure always overpowered the float needle.
The solution is to run a return line back to the gas tank with a restricted fitting in it.
Now The fuel is constantly bleeding back to the tank reducing the pressure at the carb to minimal.
I tried to get a photo but not having any luck loading it.
Thanks
OU

[old ugly]

It’s a good thing that all this ugly junk is going to be covered up.