1957 Carburetor Issue

[Tommygirl]

Frustration City!!! Help, please....I have a 1957 with a holley 4-barrel carb. I have just rebuilt it due to fuel leakage. regardless of what I do, she is still spewing fuel. I have tried rebuilding the float in the primary source, twice now. I have messed with the fuel sensor and had it wide open and tightly shut. Fuel either spills out of the sensor on top or out the stack. I am at a loss for what to do now. Why does there seem to be an influx of fuel to the float...? If it is the float, how do I fix that? Can I tighten the spring, would that make a difference?

This page contains affiliate links for which I may be compensated. As an eBay Partner, and Amazon Associate I may be compensated if you make a purchase at no cost to you.

 

[Dale Leonard]

Take a close look at the needle and seat. If the float will float in water then it is the needle and seat. compare the old one to the new one and make sure they are the same. Look at the seat and see if you can replace it. some have a rubber seat and when you clean the carb. you sometimes blow out the seat with air. Then on the other hand you may have a metal seat and have a rubber tip on the needle. This is the only place that gas can get into the carb and cause it to overflow like yours is doing. Will or should be simple to fix when you determine what is causing the problem.

 

[Flat Ernie]

Not sure what sensor you're talking about. If you mean the venturi booster, then fuel coming out either that and/or the "stack" (vent) means your float is not shutting off the fuel.

There is a screw and lock nut that adjusts the float, but if the needle/seat is lodged open by debris or a burr/damage, then no amount of adjusting will correct it.

Normally, you loosen the screw on top and then adjust the nut to raise/lower the float. If you "tighten" the nut, the float level lowers. There is a brass sight plug on the side of the bowl you can remove. With the engine idling, you want the fuel level to be at the bottom of the sight plug. Alternatively, if you remove the float bowl to check the needle/seat, you can adjust it well. Simply turn the float bowl upside down and adjust the nut so the top of the float is parallel with the top of the float bowl and you should be close enough to perfect to not have to touch it again.

 

[57bird]

another area to watch if it every backfired the power value is probably blown which will leak fuel like a sieve. it is an easy fix, if you get new power value make sure to match up the number on the power value to fit the ones in it. Aloso get the kit to install the check ball to prevent blow back. i had to do it on the 57 312 i just finished a 100% rebuild on. the original carb had at some point popped back thru it and blew them out and leaked like crazy. if its a float issue the holley site has a good guideline of what the measurement is to adjust the floats also the new needles for float do not have a tapered end they are no a flat nose which seal much better and flow better fuel when they do open. the original 4159 series 1293-1 carb do not have an external adjustment to set fuel floar level its all done with the tabs on the float arm it self. one governs how far the float can move up and close ( this is in contact with needle) they other limits the max drop of float.