Fuel dripping from accelerator pump jet- IDF Options

[tornik550]

On my dual weber 44 idf's, I am having fuel dripping out of one of the accelerator pump jets when the car is off. I assume, it is also when the car is running. There is a fairly large amount. It is pretty obvious that it is from the pump jet. I really dont think it is a float height issue cause it is only one jet that is doing this.

The car has been sitting for two weeks due to some electrical issues. The engine was running fine prior to this. Now it is running ok however I am now having a popping noise when I decelerate. It may be present at other times however the car is so loud that I cannot hear it.

Ideas?

[toolguy]

so do you mean it's dripping inside the carb from the accelerator jet nozzle, when you shut if off?? Or is it leaking from the accelerator pump cover on the outside??
If inside, I'm thinking fuel percolation in the float bowl. . look for a link to drilling pressure relief passages in the top plates

[tornik550]

so do you mean it's dripping inside the carb from the accelerator jet nozzle, when you shut if off?? Or is it leaking from the accelerator pump cover on the outside??
If inside, I'm thinking fuel percolation in the float bowl. . look for a link to drilling pressure relief passages in the top plates

Its leaking from the excellerator pump jet nozzle into the barrel of the car

[mrbubblehead]

i think the accelerator pump jet is in the bottom of the float bowl. its like a one way valve. maybe the ball is stuck?

[tornik550]

i think the accelerator pump jet is in the bottom of the float bowl. its like a one way valve. maybe the ball is stuck?

I thought that accelerator pump valve was at the bottom of the bowl. I am referring to the gray jet that has a nozzle that points into the barrel above the Venturi.

[mrbubblehead]

your right, it is a one way valve. and so is the screw that holds the nozzle in place. have you checked that screw? is it stuck open a little?

[toolguy]

the check balls keep fuel from the accelerator pump from going back into the fuel float bowl. . the top ball valve keeps air or dirt from getting into the nozzle passage. . But if the fuel is peculating from heat in the bowl, then pressure can push gas past the lower check ball and up through the accelerator body and out the nozzle. .

Start the engine cold. . run 30 secs - 1 minute.. shut it off. . look and see if its overflowing. . the engine wont be hot enough to cause percolation. .

If it's overflowing, you got something else going on, hi fuel level or accelerator adjusted wrong. . this is sort of a wild ass guess

There is a fix for percolation by drilling pressure relief holes in the top carb plate. . I'm familiar with weber triples but imagine these are similar. .Also, if it is percolation, do you have heat insulator plates under the carbs

[tornik550]

the check balls keep fuel from the accelerator pump from going back into the fuel float bowl. . the top ball valve keeps air or dirt from getting into the nozzle passage. . But if the fuel is peculating from heat in the bowl, then pressure can push gas past the lower check ball and up through the accelerator body and out the nozzle. .

Start the engine cold. . run 30 secs - 1 minute.. shut it off. . look and see if its overflowing. . the engine wont be hot enough to cause percolation. .

If it's overflowing, you got something else going on, hi fuel level or accelerator adjusted wrong. . this is sort of a wild ass guess

There is a fix for percolation by drilling pressure relief holes in the top carb plate. . I'm familiar with weber triples but imagine these are similar. .Also, if it is percolation, do you have heat insulator plates under the carbs

I did the 30sec test and I did not have any dripping. I also completely disassembled the carb and cleaned with brake cleaner. I havent had a chance to run the engine for a longer time to see what happens.

One thing that I don't understand is- if u am dealing with percolation, why would I only have dripping from one barrel of a two barrel carb? It seems that I would have te issue with both acceleration pump jets.

[toolguy]

Theoretically, you are correct. . both nozzles share 1 common fuel bowl, but 1 must have less resistance to flow than the other. . I'd imagine that if you put your finger over the hole in the nozzle that's dripping, the other one would start dripping. That might be a good test. . .
you'll need to pull up a diagram of your carb and the passages and see what goes where. . and do a web search and see if there is a fix where you drill a relief hole in the top plate. . there is for the Weber 3 barrels. .

[tornik550]

Just another bit of info that I forgot to mention. My head temps were normal when the dripping occurred. The head temp was between 280 and 310. The sender was placed on the spark plug on the #1 cylinder (I have a sender on 1 and 3). The dripping occurred on the barrel corresponding to the 2 cylinder.