[Charlie Brengun]

I got a Offy 360 dual quad with two 4160 Holley 450 CMF single fuel line inlet carburettors being fed by an unknown type and brand electric fuel pump.
The back carburettor will leak fuel if I have the pump running but the engine off.

What I'd like to do is place a Holley 12-803 http://www.summitracing.com/parts/HLY-12-803/ fuel pressure regulator in front of the carbs and send a fuel line from each outlet on the regulator to a carb.

I'm looking for a simple setup that doesn't cost a fortune as I'm going change the fuel system into an LPG (propane) only setup after getting the car registered for road use here.
But I don't want a firebomb in the mean time either and a fuel leak means it won't pas registration either.

Is my setup going to work? or do I need multiple regulators or a different type? any advice is welcome as I haven't played with this (or Holleys) before.

thanks,

[chiphead]

Most of those holley carbs will work fine with about 5-8 PSI of fuel pressure. The trick to avoid flooding with them is to set the float height properly. The fuel should be just at the bottom of the sight plug in the fuel bowl. If not, adjust the screw and locknut on the bowl holding the needle and seat assembly.

The 12-803 regulator is a deadhead type of regulator that will work fine in this application, provided that the fuel pump is OK being run in a deadhead setup.

It really depends on your fuel pump. Low to moderate output electric pumps are OK pumping into a stopped column of fuel, which is what a deadhead system is. High output pumps have to move fuel all the time, which is why a bypass system is almost always used on high output systems. The fuel that the engine doesn't consume is sent back to the tank, and this is much easier on the high output pump.

You'll get some pressure creep when the pump is ON but engine is not running. Most deadhead regulators will let their output pressure "creep" higher than their setpoint when not running. If you set the running pressure to 6 PSI, it may creep to 8 or 10 or whatever the pump's max output is when the engine is not running. If this is acceptable depends on the pressure at which the float needle gets blown off it's seat (causing flooding) or the pump strains against the stopped column of fuel in the line.

If the creep is causing problems, you can either install a small bleed line to bleed fuel back to the tank, or install a bypass regulator to bypass large amounts of fuel back to the tank. You can also install a lower-pressure pump that is more suitable for dead-heading, such as the holley Red pump.

[lust4speed]

Any regulator will work for what you want to do, and the Quickfuel is cheaper: http://www.summitracing.com/parts/QFT-30-803/

It might be a needle and seat problem since only the back carb is leaking. If it is, then a regulator might not fix the problem. Then again, setting the pressure under 4 PSI might do the trick. It takes very little pressure to keep the carb bowls full just driving around easy - especially since you have normal pressure feeding up to the regulator at the engine, and will only be reducing it just before the carbs.

[Overkillphil]

Originally Posted by lust4speed

Any regulator will work for what you want to do, and the Quickfuel is cheaper: http://www.summitracing.com/parts/QFT-30-803/

It might be a needle and seat problem since only the back carb is leaking. If it is, then a regulator might not fix the problem. Then again, setting the pressure under 4 PSI might do the trick. It takes very little pressure to keep the carb bowls full just driving around easy - especially since you have normal pressure feeding up to the regulator at the engine, and will only be reducing it just before the carbs.

X2!

[Charlie Brengun]

Thanks for the advice. I see crawling under the car and ID-ing that pump is in order and then checking the needle / seat on that carb before ordering parts that may not help sounds like the way to go.

thanks,