Leaking Venturi Boosters / Edelbrock Performer 1404

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twalace

twalace

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Anyone know what would cause fuel to leak from the Primary Venturi Boosters at idle on an Edelbrock 1404 carb? I have tried everything the Edelbrock Tech has suggested and we can't find the problem,

Rebuilt 318 with a mild cam, Edelbrock Performer manifold and Edelbrock Performer # 1404 manual choke 500cfm carb, stock distributer & stock exhaust manifolds.
 
Mrmopartech said:
You either have to much fuel pressure or the floats are too high,mrmopartech
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Nope, have a new fuel pressure regulator set at 5.5psi & floats are set at 7/16" & 15/16".

This has to be something out of the ordinary as I have already tried all the usual stuff.
 
If both of those are fine then check for something blocking the needle and seat assy.
 
What type of fuel pressure regulator/guage do you have ? A quality unit or generic knock off like the ones summit, jegs, etc. sell that are not very accurate. What is the history of your carb? bought new,used or rebuilt? If pressure is accurate would almost have to be debris blocking needle & seat like camd64 stated. Had your same problem on a 800cfm eddy and turned out to be inaccurate summit pressure guage which was reading 6psi and turned out to actually be 9.5 when finally traced problem.

Oldschoolcuda
 
Oldschoolcuda said:
What type of fuel pressure regulator/guage do you have ? A quality unit or generic knock off like the ones summit, jegs, etc. sell that are not very accurate. What is the history of your carb? bought new,used or rebuilt? If pressure is accurate would almost have to be debris blocking needle & seat like camd64 stated. Had your same problem on a 800cfm eddy and turned out to be inaccurate summit pressure guage which was reading 6psi and turned out to actually be 9.5 when finally traced problem.

Oldschoolcuda
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Fuel pressure regulator is a new $32 Mr. Gasket; think the odds of getting a bad one would be like hitting the Lotto! Just bought the car from a guy with a rebuilt 318 and a new Performer Manifold & Carb., I have had the carb apart three times now and it looks virtually new inside & out.
 
Are you reading the numbers on the regulator or have you hooked up a known good gauge to read the psi? Those Mr. Gasket regulators are not known for being accurate. A good one like Oldschoolcuda was mentioning can be had from someone like holley, mallory, aeromotive, etc. http://www.summitracing.com/parts/HLY-12-704/
 
camd64 said:
Are you reading the numbers on the regulator or have you hooked up a known good gauge to read the psi? Those Mr. Gasket regulators are not known for being accurate. A good one like Oldschoolcuda was mentioning can be had from someone like holley, mallory, aeromotive, etc. http://www.summitracing.com/parts/HLY-12-704/
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I tried the regulator at the 1psi setting so even if it was mis-calibrated 1-4.5psi it should have made a difference. Not looking into running braided lines on this car as that would be required using one of the other regulators mentioned.

Think the next step is to get a vacuum gauge and see what reading I get from the vacuum port on the carburetor.
 
I would check the fuel pressure with a gauge. Those things are more of a restrictor than a regulator, plus you won't know what psi your getting without actually testing it.
 
twalace said:
I am hesitant to try that as the Edlebrock Tech was pretty adamant about the factory settings; pretty much everything I have checked on the web says to use factory specs.
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just as a test id try lowering the float.ive seen what your describing many times and it was 1of 2 things;high float or bad needle and seat.if lowering the float dont help id replace needle and seats after you actually check your fuel pressure with a gauge.
 
After reading numerous posts on various sites the problem was the idle set too rich and fuel was by passing the Idle Discharge Port on the bottom of the throttle blade!!!

You need to adjust one idle mixture screw for the highest hg reading then the other one, after that go back and set your idle and repeat until the fuel stops pouring in the venturis and you have a good idle. Also advancing the distributer a bit will help with this problem as well.

Need to do some fine tuning now with the metering rod springs and I think 15hg of vacuum is too much??? Oh yeah, went out and bought a Vacuum Gauge which I can also use to check fuel pressure! :read2::love7::cheers:
 
Used the new vacuum gauge to test my fuel pump tonight and found out my stock fuel pump was also part of the problem as it's putting out 7psi without the regulator. Looks like I had two problems at once going on, no wonder the guy I got the car from couldn't get it to idle!
 
How about too much heat under the carb? (fuel percolation...AFB's are prone to it) Do you have the crossover blocked? Try a heat insulator under the carb, or run cold water around the carb base area and see if that stops it. It has worked for me in the past.

Just my thoughts....
 
65Val said:
How about too much heat under the carb? (fuel percolation...AFB's are prone to it) Do you have the crossover blocked? Try a heat insulator under the carb, or run cold water around the carb base area and see if that stops it. It has worked for me in the past.

Just my thoughts....
Click to expand...

Crossover?
 
twalace said:
Crossover?
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Yup...the exhaust heat crossover passage under the carb in the intake manifold. It heats the carb base during cold driveaway. AFB's are very sensitive to this heat,and if its too hot, the fuel in the bowls will percolate out the boosters.

Also, make sure the "flapper" valve in the pass.side exhaust manifold is open when the engine is hot. If its stuck closed, it will trap heated exhaust air in the crossover passage.

Been there, done that.
 
65Val said:
Yup...the exhaust heat crossover passage under the carb in the intake manifold. It heats the carb base during cold driveaway. AFB's are very sensitive to this heat,and if its too hot, the fuel in the bowls will percolate out the boosters.

Also, make sure the "flapper" valve in the pass.side exhaust manifold is open when the engine is hot. If its stuck closed, it will trap heated exhaust air in the crossover passage.
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Funny you mention all this overheating stuff as just when I thought I had everything licked I fired up the car the other night and noticed it started spitting a little fuel out of the passenger booster again! Noticed the car was running hot and the radiator was cold! This is the first time this has happened so I don't know if I have a bad thermostat or whats going on now. When I squeeze the bottom radiator hose I hear the thermostat make noise in the housing so I am suspect it has gone bad.

Exhaust Heat Crossover Passage; Car has an Edelbrock intake manifold so would that still apply?

Where is the Flapper Valve located on the exhaust manifold?
 
Where is the Flapper Valve located on the exhaust manifold?
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Passenger side at the exit of the manifold. It should be able to be twisted by hand and a external spring should be seen and free.

Exhaust Heat Crossover Passage; Car has an Edelbrock intake manifold so would that still apply?
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The head, is stock, has this passage. The intake manifolds from Edelbrock will have it on the Performer, LD4B, LD340, RPM, Torker(s)
The race intakes will not have them.
 
Exhaust Heat Crossover Passage; I wondered what those slots were that were open under the carb! Yeah those are open and clear on both sides.

Will have to look for the flapper valve as I don't recall seeing that. Contemplating what to do with the exhaust at this point, not going to put headers on the car now as the few companies that make them for this car want too much $$$ for them!

Thinking of running a single Flowmaster from the stock exhaust or seeing if there is room to run a duel setup with Flowmasters and a balance tube. Any suggestions...:read2:
 
twalace said:
Funny you mention all this overheating stuff as just when I thought I had everything licked I fired up the car the other night and noticed it started spitting a little fuel out of the passenger booster again! Noticed the car was running hot and the radiator was cold! This is the first time this has happened so I don't know if I have a bad thermostat or whats going on now. When I squeeze the bottom radiator hose I hear the thermostat make noise in the housing so I am suspect it has gone bad.

Exhaust Heat Crossover Passage; Car has an Edelbrock intake manifold so would that still apply?

Where is the Flapper Valve located on the exhaust manifold?
Click to expand...

rumble has pretty much covered it. All street-style Edelbrock intakes have the X-over passage.

If you still suspect that heat is causing the dripping fuel, run cool water around the carb base to see if that stops it. If it stops, then I'd suspect heat in the carb base is your problem.

Below is a pic of the bottom of an Edel. intake. Area inside yellow circle is the exhaust heat x-over passage.
 

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he already fixed the problem guys=he was running on the mains instead of idle circuit due too much blade opening/idle speed set too high.

when he lowers it down the rpm will lower too, but can be brought up to the necessary rpm by raising the initial timing to compensate...another reason why a higher than stock spec initial timing is a good thing.

heat cross overs are not the culprit for this, all factory stuff would be running like sht if it was.

fwiw -eddy carbs do have to most issues with this, btw.
 
1wild&crazyguy said:
heat cross overs are not the culprit for this, all factory stuff would be running like sht if it was..
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Well, I've seen this many times over the years I've been involved with Carters/Edelbrock AFB's, and blocking the x-over or a heat shield has fixed it. I wasn't saying this was THE answer, just a suggestion.

Original Carters didnt have this problem as much as the newer designs do. Even though they look the same, the newer AFB's are different than the older ones.
 
Did not see a "Flapper Valve" on the passenger side exhaust system, maybe that is specific for certain year cars??? Did find it interesting the car had a 195* thermostat which I think is a tad too high, also seemed to open erratically when put in boiling water. Dunked it three times with three different results, 1st time didn't open, 2nd time partial opening, 3rd time fully open. Going to replace it with a lower temp t-stat and hope water will flow again through the radiator. When I drained the coolant it had zero rust or particles in it so I think the radiator is in good shape. Do think the erratic t-stat might be contributing to a possible heating of fuel in the carb.
 
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