Primary and Secondary Idle Mixture Screws, 4 same or only 2

Discussion in 'Engine Topic' started by 71Camaro707, Dec 6, 2018.

  1. 71Camaro707

    71Camaro707 New Member

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    When I bought my car I found that the Holley 4150 4bbl secondary idle mixtures screws were all the way closed [all the way clockwise] and only the primary idle mixtures screws were opened. I figured all the the screws should be the same amount open to equal the air fuel ratio withing the complete intake manifold [Edelbrock Victor Jr]. So should I adjusted all 4 or readjust to just the primary?
     
  2. CorkyE

    CorkyE Veteran Member Lifetime Gold Member

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  3. 71Camaro707

    71Camaro707 New Member

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    Thank you.
     
  4. 1980RS

    1980RS Veteran Member

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    Single plane intakes are not as touchy about 2 or 4 corner idle as dual planes. Remember to set the transfer slot no more than .020 looking at the carb overturned, too far open make the engine run pig rich and the screws might not do anything.
     

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