Quick fuel 850 DP

Discussion in 'Holley' started by Romel, Aug 21, 2019.

  1. Romel

    Romel Well-Known Member

    Got the replcment carb from summit after the first one was screwed up. I have ben tuning this one for a few days and have it idleing good and great takeoff but at steady rpms i get a stumble. Almost feels like a miss or its loading up. I increased the air bleeds from 70s to 74s and it still does it. As soon as i give it a little more gas the stumble goes away. Any help would be appreciated. Sick of carbs. Lol. Also does anyone know what the two screws closest to the squirters are. I know the outside one are air bleeds but not sure of the others. Thanks
    Last edited: Aug 21, 2019
  2. sean Buick 76

    sean Buick 76 Buick Nut Staff Member

    try adjusting the idle mixture screws?
  3. LARRY70GS

    LARRY70GS a.k.a. "THE WIZARD" Staff Member

    This is the second carburetor you are having problems with, am I correct? I find that highly suspect. Holley carbs work out of the box. That's not to say that they don't require tuning, but the type of problems you are experiencing suggest you have a more basic problem somewhere else.

    What ignition are you running? Have you checked for a vacuum leak?
  4. Romel

    Romel Well-Known Member

    Checked vacuum, no leaks. Timing is 12 initial total 34 all in by 2700. I can put the old holley back on and it runs fine. Dont make sense to me either
  5. hugger

    hugger Well-Known Member

    The old carb may be concealing an issue due to it itself having an issue,...I've seen this a few times actually one carb mask an underlying problem and when you put an actual correctly working unit on it runs worse
  6. Romel

    Romel Well-Known Member

    Ok. Finally starting to get this thing running right. Up the jets and air bleeds. Helped a lot. Might need smaller power valve, but got the stumble almost completely gone. Idles great and excellent take off. 16 inches of vac at idle. Im getting there
  7. 73 Stage-1

    73 Stage-1 Dave

    Have you worked on the accelerator pump shot?
  8. telriv

    telriv Founders Club Member

    Too much timing advance via the vacuum advance advancing too far????
  9. shiftbyear

    shiftbyear Well-Known Member

    Float levels correct?

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