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-   -   quadrajet problem (https://classracer.com/classforum/showthread.php?t=24757)

rjarrell 03-29-2010 03:21 PM

quadrajet problem
 
quadrajet loading fuel on idle
adjusting air and fuel does not make any differance.
newly rebuilt carb
new fuel pump
new gas line feed and return to tank
new gas tank
350 chevy rebuilt , fresh start
any ideas?

Chipper Chapman 03-29-2010 03:33 PM

Re: quadrajet problem
 
May seem stupid, but i've done it so i'll ask, If the carb has been rebuilt, are you sure you have the correct body to top gasket? In some apps some are very close to right, but not right. Had one with the same symptons and thats what turned out to be. Also, the float could be too high, needle/seat stuck open or out of place

raceewing 03-29-2010 03:36 PM

Re: quadrajet problem
 
I just had the same problem on my thermoquad, had a bad float.

rjarrell 03-29-2010 03:51 PM

Re: quadrajet problem
 
did not rebuild carb myself
was sent to the Toronto area, to a company that rebuilds carbs.
Just making sure i cover all bases before i send it back.
I have also been told it could be a low vacuum problem, or a
fuel pressure prob. will check it out first. Thank's for the help.

Mike Savelle 03-29-2010 04:07 PM

Re: quadrajet problem
 
had the same problem . replace the float with a new one

Bob Pagano 03-29-2010 04:28 PM

Re: quadrajet problem
 
Check fuel pressure, some will piss by with over 6-7 lbs

GTX JOHN 03-30-2010 12:12 PM

Re: quadrajet problem
 
If you are going to race your car, the carb requires a fair amount of specialized mods. You didn't say if you used a generic rebuilder or race specialist. It could certainly be a simple fix as suggested and probably is.....I have found it a really challenge to make Stock/SS car idle (low vacume/lots of overlap in cam). Danny Ashley is the one that I recommend to rework one....very approachable and patient with me: #1 in my book!

tj310 03-31-2010 11:00 AM

Re: quadrajet problem
 
Everybody has their stories. I have found that a pure stock Quadrajet may work fine on a 10 sec superstocker...Thanx Trevor

Run to Rund 03-31-2010 12:25 PM

Re: quadrajet problem
 
Two likely things are stated above: excessive fuel pressure to the carb, and a bad float or needle valve. Another possibility is leaky plugs on the bottom of the fuel bowl. you have to remove the throttle body to see them.

Marvin Robinson 04-09-2010 10:52 AM

Re: quadrajet problem
 
In addition to the above, Check & make sure the that the top gasket is not binding the power valve needles - there is a slot in the gasket that the hanger has to go thru, and it can easily get caught on the power valve body when you install the top lid of the carb if you're not careful. Also, check for leaking at the fuel well plugs at the bottom. Sometimes they will leak when subjected to the carb cleaning solutions used, and most good rebuilders will seal the bottom of the well with epoxy, pipe plug, etc. Both of these conditions could cause unmetered fuel to drip or flow into the manifold, and render the adjustment needles unresponsive.


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