[lil-vulky]

is it ok to use electric fuel pumps on a carburator? i have a 9psi electric fuel pump which runs when the keys on, but my carb drips petrol when sitting is it because the fuel pump is constantly pushing fuel into the carby even when its full and theres no return line for the excess fuel.

is it better to get a mechanical fuel pump and disconnect the electric one or not?

its a ford 460 with a 750holley carburator in an xj6 jaguar

could someone give me some ideas on what to do or if its fine as it is? car runs fine jst not sure if its bad for me to have an electrical fuel pump

[RWENUTS]

Put a regulator on it with a return to the tank. Your carb would like 6 lbs. maximum for pressure.

[lil-vulky]

if it hasnt got a return line already there how would i go about making one? does it have to be steel lines or could i just buy a long fuel hose and use that?

[RWENUTS]

On second thought. First try a good regulator then if needed tie in a return line. Use a stee tubing line though if you do.

[lil-vulky]

ok thanking you lots should i set it at 6psi for the regulator or lower?

[RWENUTS]

Experiment!! Your carb might like less.

[techinspector1]

Originally Posted by lil-vulky

ok thanking you lots should i set it at 6psi for the regulator or lower?

More pressure will not make more horsepower. What it will do is to overpower the needle and seat in the bowl of the carb and blow raw fuel into the intake manifold, creating a tuning nightmare. Shoot for 5 psi. You want high volume to prevent fuel starvation, with large diameter lines, not high pressure.

[cdminter59]

Check out the different electric fuel pumps Holley has. http://www.holley.com/data/products/...lPumpchart.pdf. Me personally, I wouldn't use nothing under a 12-150 with -8an fuel supply line. I have the pump and regulator and -8an supply line installed but thinking of installing a return line to the tank. I also have one of these Billet pumps that I won from an online contest Holley was having. I don't have the regulator or filters for it. http://www.holley.com/data/Products/...R10569rev4.pdf

[mustang 671]

hi lil vulky

i have recently had a problem with fueling too . long story but will tell you what i experienced and what i did. some people will tell you to do all sorts, returen lines etc. up to you but if i was you i would start with the basics and logic then face the problems if and when they come.

i have 2x 600 holleys on top of my supercharger , i was running a mech hi volume elderbrock fuel pump. i change it as i liked the idea of adjusting the carbs to 100% float levels and checking for leaks etc before the engine was running . so im with you on the electic fuel pump , secoundly depending on how old your carb is i had problems with my needle valves not shutting off. even when i put in new ones they are still a bit sticky, after more use they are starting to work alot better , may be a idea to be a rebuild kit and clean it up and change the bits.

i incorrectly bought a bosch electric fuel pump and it sent the fuel pressure up to 12 psi and i soon realised i had bought the wrong pump off of ebay and it was a type that required a retun line and something i didnt need, and i dont think you need .

so as i always had a regulator i rang "real steel " a good american auto shop over here in the uk and they reccomended a holley red top pump . it is the more quieter pump and doesnt require a return pipe .

have fitted it and its great . i had a problem that i couldnt fit it under the car and by the fuel tank. so i had to bleed it to get it pumping as i fitted near the engine bay but on the other side of the inner wing .

i would reccomend you purchace a holley regulator and a holley electric pump. the regulator will come factory set at around 6 psi and is fine for holley carbs. ( most holley carbs will take alot more then 6.5psi as reccomended as their max pressure. most will take up to 8 psi, - speak to any good carb specialist )

house the holley pump as near to the fuel tank as you can but personally i dont like them under the car for obvious reasons. keep away from heat , mine works well under the front wheel arch at the front of the car. but i still need to see how it performs in wot , however i dont feel you will have a fuel delivery issue even if you house it away from the tank. i may have to move it further back, these pump are better at pushing than pulling fuel.

finally if you want to save money and want to work with what you have then simperly put a tee piece at your carb inlet and then say 12" away ( say near the friewall ) place a pressure relase valve set @ 6.1 psi then just a simple rubber return pipe ' the outlet into the TOP of the fuel tank . same as the fuel goes in when you fill up. DO NOT put it under the fuel level as this causes all sorts of problems which will take too long to go into. pressure issues. flow. wrong fuel readings. etc. etc.

however i would prefer the option i have done, depends on what budget you have. both are easy to do but the cheaper option is a return pipe. but you only require it as you have the wrong pump. so i feel you are fixing a problem due to the wrong pump. i would buy the correct pump personally as i dont like the idea of a return pipe. another risk in my opinion. one fuel line is bad enough . oh and a 3/8 fuel line will be fine for what you need. and remember its not fuel pressure you should be hugly concerned about as you mainly need fuel flow @ wot as a lean mixture due to lack of flow is not good . no point having great pressure but no flow when you need it the most.

hope that helps somewhat.

good luck bud

[boatbob2]

You can also put a fitting into your gas fill pipe,if you cant get it into the tank,TAKE the pipe OFF,before welding a fitting...Been There,Done That...........

[mustang 671]

Originally Posted by boatbob2

you can also put a fitting into your gas fill pipe,if you cant get it into the tank,take the pipe off,before welding a fitting...been there,done that...........

he he he

[lil-vulky]

Originally Posted by techinspector1

More pressure will not make more horsepower. What it will do is to overpower the needle and seat in the bowl of the carb and blow raw fuel into the intake manifold, creating a tuning nightmare. Shoot for 5 psi. You want high volume to prevent fuel starvation, with large diameter lines, not high pressure.

i think thats whats been happening because when i was trying to tune the carb and set the mixture screws etc it wouldn't work no matter if i turned the screws all the way in or out the rpm would never change. completely even forgot that my fuel pressure is probably causing that, will start off with a regulator and go from there.

haven't got much money left and my fuel pump at the moment is brand new so will just stick with it, its a mr gasket one, have 2 of them because twin fuel tanks but only 1 runs at a time, im hoping there is already a return line on the car but im not sure need to wait for rain to stop before i have a look around.

but thanks for all the advice and help, if a regulator doesn't fit it ill get one of those red top holley pumps