crunchyskippy

Okay, I'm still messing with my carb...

I recently rebuilt my ford 2 barrel carb. (Thanks to everyone that helped me with that.)

This afternoon I noticed that there is still fuel leaking on the manifold. It looks as though its coming from the idle mixture screws. Is this possible? Is there supposed to be some sort of "O" ring to keep it from leaking...or maybe my threads are not tight enough? Any advice would be greatly appreciated.

Also, while *attempting* to adjust the idle mixture screws, there was no discernable difference between the 1.5 turns out that I started with and a fully seated (all the way in) comparison. I would have guessed this would have stalled the engine or at least made it idle roughly. Nope, it just idled away. (However, I did not try both sides in at the same time.) Also, I didn't see any fuel pouring over (i.e. a stuck float), but I certainly couldn't figure out how it was still running.

Since I'm out of daylight I thought I'd pick your brains. What am I missing?!?

Thanks as usual.

restomod66

Time for another carb!!! Fuel leakage can be very dangerous to your car and any chance of ignition could spark a disaster!!

Soaring

The left screw makes a difference at idle, right? The right one is for higher speeds. Just turn it out about 2 1/2 turns.
Adjust the left one where the engine idles smoothly. No, this is not the scientific approach, it's just what works for me with my Autolite/motorcraft 2V on my 289.

69FECoupe

The mixture screws on the carburetor both adjust the idle, they have very little effect above idle speeds. The main jets regulate the high speed mixture.

THUMPIN455

If I remember correctly there should be a cork gasket around the needles too, usually they stay in the carb housing/baseplate and people dont notice them.. Look in your kit and see if there are a few very small round pieces of cork in there.

valley firearms

Thumpin is right. There should be a small cork ring gasket.

85lebaront2

The small cork gasket is on Holley carburetors, not Ford/Autolite/Motorcraft carbs. If it is a pre-emission model, then the idle screws should be roughly 1 1/2 turns from seated. If it is an emission model, 1968 up or a service carb (will usually have a number like D2PF, C8PF on it) then the screws will be 2 1/2 - 3 turns out. You can tell the difference if you look at the mixture screws. Early carbs (up through 67 US, 65 or 66 California) will have fairly stubby points, later ones are longer. If you are leaking fuel, check the accelerator pump cover, make sure it is flat and tight, they are very prone to leaking there as they get older. One item, if you have an emission carb, the idle screws are mixture trim, and will not have as much effect as ealier models.

boeing747arowair

Get urself a new Edelbrock 4 bbl

Yonco

I have a holley 4 barrel 600 CFM JUST rebuilt, profesionally, taken down to bare, rezinc( looks chrome) coated, new gaskets and everything is new. I put it on and cant get it to run right( less than 30 mins run time)... dont like the idea of tuning this particular one( holleys are a pain i hear- so thats steering me to edelbrock) and... i dont want an electric choke. want to buy it? 200$ shipped. And ill get something else! -Jon

Decurion

two words for you: POWER... VALVE Its blown. As long as no other fuel is leaking (it would be visible in the throttle bores) when you run the idle mixture screws in, it should stall. Simple as that because at an idle all the fuel going into the engine has to go past those 2 screws.