Results 1 to 2 of 2

Thread: air fuel mixture

  1. #1
    pedigo78 Guest

    Default air fuel mixture

    I air fuel mixture is wrong and i need to adjust it but worried about messing it up more. So if i just wanted to lean it out a little which way do i need to turn the mixture screw. my truck stalls when i punch it and occasional backfires, and has alot of black smoke when i gun it. and sometimes when i turn the truck off it still stalls and backfires. I am worried that if i dont lean it out a little it will mess up the motor. i am planing on getting it tuned at my local speed shop, but in the mean time i would like to lean it a bit. it also only gets like 75 miles to a tank of gas, yes a tank of gas.

  2. #2
    rickyr Guest


    In is lean and out is rich
    first get the engine up to temp,
    then kill it,
    then screw the screws all the way in
    and back them out 1 1/2 full turns
    restart the engine,
    with it up to temp and @ idle
    turn one in 1/4 turn then the other one in 1/4 turn
    go from one to the other 1/4 turn at a time
    until you hear a RPM drop
    then back both out 1/8 turn
    oR if you have a vacuum gauge keep all mixture screws the same amount of turns to get the highest vacuum reading
    you can

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
About us
Holley has been the undisputed leader in fuel systems for over 100 years. Holley carburetors have powered every NASCAR® Sprint® Cup team and nearly every NHRA® Pro–Stock champion for four decades. Now, Holley EFI is dominating the performance world as well as our products for GM's LS engine. Holley's products also include performance fuel pumps, intake manifolds & engine dress–up products for street performance, race and marine applications. As a single solution, or partnered with products from other Holley companies - Hooker Headers, Flowtech Headers, NOS Nitrous, Weiand, Earl's Performance Plumbing, or Diablosport - Holley products can give you the edge you need over the competition.
Join us