Quadrajet Problem Solving > Diagnose a Quadrajet carburetor problem
rebuilt dualjet, now flat spot
1clnlj:
Don't know if you deal with the small Dualjet carbs but pretty much the same as a quadrajet just 2 less barrels. I just rebuilt the carb off of my 81 Grand Prix with a 265 engine and now I have a flat spot just as I accelerate off idle. Everything else is perfect, high idle kicks down to idle and you can't even feel the car running at idle. Any ideas? I did replace the accelerator pump thinking that maybe I had a faulty one, but that did not help.
Cliff Ruggles:
I would get one of our pumps for it for sure, and re-seat the check ball while it is apart. NONE of the over the counter accl pumps available currently are worth two squirts of duck poop. I spend countless hours each week listening to stories where folks kitted their carbs and have similar experiences, most are related to the "blue" seal on the pump not working well in this new fuel.
Ours will not fail in this new fuel and comes with a lifetime warranty if it does....but I've never once to date had to send one out.
Check the fuel inlet seat to make sure it is the SAME size as the one removed, and float set at the correct height.
I would also check the primary metering rods to make sure the hanger is level and EXACTLY even. I'd tap the hole over the APT adjustment for external access to the APT screw while it is apart.......Cliff
1clnlj:
Maybe I should have just sent this out for rebuilding. What would you charge and do you somehow test it? What do you mean by 're-seat the check ball'? I have the 'bible' Pontiac Service book and it does not mention anything about this. And your accelerator pump shows 2 springs, mine only had one and it also did not have that circle looking retainer clip. Or is that just a generic picture and might not pertain to my carb.
Ethan1:
What DualJet are you working on? I love those carbs! I did a 165 model last year. Pretty unique carb.
What Cliff means by re-seating the check ball is, there is a check ball underneath a screw with a protruding "nose". It is next to the jets and accelerator pump well.
As for the accelerator pump, one spring is for the accelerator pump shaft itself, then the retainer goes over that to hold the spring in place on the accelerator pump shaft. The other spring goes into accelerator pump well of the carb.
Ethan1:
Look at the two beginning photos of the post #2 for the screw and check ball:
http://67-72chevytrucks.com/vboard/showthread.php?t=447194
Also, the accelerator pump assembled:
http://quadrajetparts.com/images/thumbnails/125x100_Q1004-w600.gif
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