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Thread: Brawler 570 stupid rich, mixture screws not leaning it out.

  1. #11


    Pulled carb. Slots are a little past square, but I noticed the curb idle screw isn't touching the arm at all, by a considerable amount yet. My idle was 8-900 RPM.

    I adjusted the screw behind the choke that contacts the pink/red plastic thing (sorry, dont know proper name of plastic thing) to get back to square.

  2. #12


    That red plastic thing is the fast idle cam that ups the idle when the choke is on. The adjustment screw for the secondaries is in the base plate. See picture.
    Click image for larger version. 

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    Make sure you open up the choke all the way before you try to adjust the idle speed. The choke staying closed would also make it pig rich if it's not opening all the way when the engine is warmed up.
    Twin Turbo 400 SBC
    748 RWHP@11.9lbs/Boost
    1250 Super Sniper EFI,
    SHP Block, JE Pistons
    Eagle Rotating Assembly
    CNC Ported Edelbrock heads

  3. #13


    So the slot is square, idle is closer to 800 than 900, screws are still only half a turn off the seats. It's noticeably better, but could likely still be improved upon. It doesnt gag you sitting at a light and the fumes in the garage are much less.

  4. #14


    Choke wide open? Try turning your idle mixture screws in a 1/8 turn at a time. Don't worry about what the vacuum gauge shows, Give the engine what it wants. If it's still bad, lower your float 1/2 to 1 turns and drop the fuel pressure to 5.5. Do you have a wideband O2 on the car?

  5. #15


    I have a wideband O2 sensor, but something is wrong. It just shows a steady 22.5 and doesn't move. I have another sensor, it's used and I don't know if it's any good. And choke is wide open. Also for what it's worth, I'm running 87 non ethanol fuel.

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