Q-jet tuning??? Thought I seen a thread

Discussion in 'The Venerable Q-Jet' started by lostGS, Sep 8, 2012.

  1. lostGS

    lostGS Well-Known Member

    While I am not a pro mechanic I take stabs at it. I am having some slight bog problems with my wagon. I have rebuilt (with Greg's carb kit) my carb it runs, starts etc. but I get the hesitation the quadrajet is down falled for. I have seen a Q-jet tuning thread on here but I cannot find it. Nope didn't come up with a search. Anyone have a link to the q-jet tuning thread or any q-jet tuning. or any help tuning this thing. It is the stock Qjet on my 71 Sportwagon, TH350. with headers and duals. I get about 13-15lbs vac at idle and about the same at cruise. I left the adjustments the same after I rebuilt it. ( didn't touch the needle adjustment)

    Please help

    Tim
     
  2. robs71redriv

    robs71redriv robs71redriv

  3. Bigpig455

    Bigpig455 Fastest of the slow....

    Is the bog right off idle, cruising speed or into the secondaries? Makes a difference. Off idle or cruising it could be float level or accellerator pump, secondaries it could be air valve tension or pullover system restriction/positioning.

    The Riviera link is a great document, you might also try Cliff Ruggles book - that goes into great detail.

    I love Q-Jets, but I've never gotten one right first shot, each one took some fine tuning.
     
  4. Obie455

    Obie455 Well-Known Member

    If you can't get it fixed I strongly recommend Ken G at Everyday Perofrmance. He straightened out a quadrajet that had me so frustrated I was ready to drive the whole car into a tree! Got it back from him and it was like night and day! Great guy, great service and a board member? :TU:
     
  5. Bigpig455

    Bigpig455 Fastest of the slow....


    x2 on Ken - He did my 66 Q-Jet, and did a fantastic job. Still my favorite carb.
     
  6. techg8

    techg8 The BS GS

    what leaps out at me is the 13-15inHg vacuum reading.

    stock engine should be on the order of 18-20

    recheck your idle mix screw settings. Tune them for maximum vacuum reading at idle rpm. Add fuel until the engine doesnt respond.

    check for vacuum leaks. - throttle shaft loose?

    when the car is idling, try to choke it out by covering the primaries with your hand. You should be able to choke it right out.

    just some quick thoughts, but that vacuum gets my attention.
     
  7. lostGS

    lostGS Well-Known Member

    Ken, I will try that. Shoot me a pm on what you would charge to go through my carb. thanks

    Tim
     

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