Weber idf 44 leak!, Help! Options

[Milkman7286]

Hello all,
I've got a 71 4 banger with dual weber idf 44's on it and the driver's side front barrel has sprung a leak.
Here is a little detail before I go further into the leak:
The webers are about 6 years old and have about 7,000 miles on them. The car sat in storage for about 3 years but was started and driven every 6 months or so. For all I know this leak has been there all along and I never noticed, but I don't think that is the case.

The leak:
The carb is leaking gas down the front barrel on the drivers side. It appears to be coming from the progression / transition holes but it is hard to tell. The other thing I noticed is that the gasket just above the float bowl is very wet and the gasket between the carb/manifold is also a little wet. I have been dealing with this for about 2 weeks now and have read every possible thing I can find and none have solved this.

Here is what I have done so far:
-Float set at 10.5mm measuring with the gasket in place.
-Butterfly was loosened and repositioned in the bore.
-Needle and seat have been tested both with fuel and air and are good
-float is free in movement and does not hang up in the bowl
-float is still a float and does not sink
-idle circuit is free flowing and not clogged
-fuel pressure is 2.5
-float bowl gasket does not accidentally cover any holes or vents


Any ideas on this one? I feel like I have tried everything and for the life of me I can't figure it out. Last night I was watching the fuel puddle on top of the butterfly and it seemed like maybe it was coming from the seam at the float bowl gasket. Any reason why fuel would be coming from there?

As FYI:
This happens when the car is hot or cold, doesn't matter.

[jmill]

What keeps the fuel from dripping on its own on these carbs? I mean the mixture screw is at the bottom of the carb and the progression ports are fairly low too. Since gas is above these points what stops fuel from leaking just by way of gravity?

The idle circuit takes its fuel from the main fuel well. It then loops up higher than the float level and then comes back down to the progression ports and mixture screw. The idle air jet is at the top of the loop which breaks the siphon and stops the flow. A plugged idle air jet won't break the siphon and fuel will continue to flow until the float bowl is empty. Your idle mixture will also be super rich.

To clean it, remove the idle jet on the offending cylinder and blow from the vent (idle air jet) down. You'll easily see when it's clean. If there's crud, make sure to get it out so it doesn't plug up the idle circuit. You can stick something in there as long as it doesn't booger up the hole. Get that whole circuit super clean.

[Milkman7286]

What keeps the fuel from dripping on its own on these carbs? I mean the mixture screw is at the bottom of the carb and the progression ports are fairly low too. Since gas is above these points what stops fuel from leaking just by way of gravity?

The idle circuit takes its fuel from the main fuel well. It then loops up higher than the float level and then comes back down to the progression ports and mixture screw. The idle air jet is at the top of the loop which breaks the siphon and stops the flow. A plugged idle air jet won't break the siphon and fuel will continue to flow until the float bowl is empty. Your idle mixture will also be super rich.

To clean it, remove the idle jet on the offending cylinder and blow from the vent (idle air jet) down. You'll easily see when it's clean. If there's crud, make sure to get it out so it doesn't plug up the idle circuit. You can stick something in there as long as it doesn't booger up the hole. Get that whole circuit super clean.

Thanks for the breakdown. That is super helpful to me because I am a very visual person and since I can't see what is going on inside the carbs I can't understand it exactly. I'm assuming that vacuum pulls the fuel through this system when operating correctly?

You know, I actually have done the above a few times and when I do it sprays carb cleaner through the idle circuit very cleanly and with good pressure so I'll have to step it up and stick something through the hole. Any ideas what to use? I asse I need something strong but thin.