1fasZ

I have a 6 month old 670 holley avenger carb and no matter how far I screw the needle seat down in the back float bowl,I can't get the fuel level down...The front bowl works fine.
I have a Edelbrock Victor racing Series fuel pump with bottom pump plate I have a Barry Grant bypass unit located at the back of the carb to return the excess fuel to the tank on the bypass and regulate fuel pressure I have a fuel pressure guage screwed on it and at idle it reads 4-9 psi (fluctuates alot, IS THAT NORMAL?)but when I rev it up it reads a steady 6 psi.
I tried adjusting the bypas diaphram but it would not stop the fluctuation.
Well that is about all I know. Any help with this would be much appreciated...
Thanks

SSC

Well the 1st problem is your fuel pressure is too high. You need to get an external inline pressure regulaor and set it to 6psi max I would go with 5psi.
The second problem is your needle ans seat is sticky and probably needs to be replaced. Just unscrew the nut on the float adjustment and thats how easy it is to take out. You might be able to spray the needle and seat with carb cleaner than dunk it in some ATF. This might help but probably not, it worth a try.

1fasZ

3 questions
If my pressure is to high why isn't the front flooding also?
Why can't I get the pressure down enough with my bypass diaphram?
Why does it fluctuate so much at idle? 4-9 lbs:lala:

SSC

To be honest I dont know why your diaphram is not working, the fluctuation in pressure is directly caused buy this malfunction. How did you hook up your S/A's fuel lines? Its possible that the rear bowl is receving more fuel than the front due to the fuel line setup. A few thing may be happening.
1. For some reason some debree made its way to the back fuel bowl and lodged itself in the needle and seat.
2. You have more pressure going to the rear fuel bowl overpowering the float.
3. Your pressure guage is faulty. I doubt it.

I would try this, limit the fuel pressure with a clamp or vise grips on the fuel line, then try to adjust the rear float. If it doesent adjust then we know the needle and seat is faulty. I dont know much about the fuel pump your using or the regulation system, by the fluctuating pressure we know that something is screwy. Maybee the diaphram in the regulator is punctured. This could cause problems like you mentioned. Try a cheapo fuel pump $6 or your old one. Id rather have a azone special that works correctly than a expensive one that doesent. I'm running a plain holley street pump which is just a cheap pump but is chrome I think its puts out 5psi and so far I havent had any problems with fuel starvation at WOT.

Try tthe stuff I mentioned and see what you get.

Damon

If your rear float is playing "sumarine commander" it could also cause the fuel level in the rear bowl to constantly be too high.

If the needle valve was bad (leaking even when closed) you would flood out the carb almost instantly after startup.

Honestly, Holley float have a TON of adjustment range in them and you should be able to get the fuel level down. Remember on a Holley-style carb's that it's the NUT that adjusts the float, the screw on the top is merely the lockdown to hold that adjustment (exactly the opposite of what most people expect).

1fasZ

This is how I have the fuel line setup except I have a mechanical pump that has 14-15 psi . P.S. I have tried different needle seats and different diaphram.
Thanks ,
Mike
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