Idle mixture tuning question?
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Idle mixture tuning question?

  1. #1
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    Default Idle mixture tuning question?

    I am running a RPM air gap and quick fuel 850 on my 460 Chevy. My under load jetting is right where I want it. My Idle mixture is rich on 1,7,6 and 4 wich is the lower half of the dual plane and the drivers side of the carb. I am assuming I need to lean up my idle mixture on this side of the carb. Does this sound right?

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    Senior Member ol guy's Avatar
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    Quote Originally Posted by jungledave View Post
    I am running a RPM air gap and quick fuel 850 on my 460 Chevy. My under load jetting is right where I want it. My Idle mixture is rich on 1,7,6 and 4 wich is the lower half of the dual plane and the drivers side of the carb. I am assuming I need to lean up my idle mixture on this side of the carb. Does this sound right?
    NO!!! M

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    use a BBC to pull a BBC devanwon's Avatar
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    460 chevy??

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    B.A.M aka "Black Azz Mike 396_Ways_To_Spit's Avatar
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    Quote Originally Posted by devanwon View Post
    460 chevy??

    FYI, that is a BBC that is bored .030 over. Obviously you just made yourself look like an idiot

    So before you laugh at someone else, make sure that you know what the fock your talking about....................
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    Quote Originally Posted by 396_Ways_To_Spit View Post
    FYI, that is a BBC that is bored .030 over. Obviously you just made yourself look like an idiot

    So before you laugh at someone else, make sure that you know what the fock your talking about....................
    Let him catch his breath next time.........................FLMAO


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    Quote Originally Posted by Fo Sitty View Post
    Let him catch his breath next time.........................FLMAO

    Thanks, Now back to my question on my Chevy 460 11to1 .030 over 454 Chevy, anyone

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    Quote Originally Posted by jungledave View Post
    Thanks, Now back to my question on my Chevy 460 11to1 .030 over 454 Chevy, anyone
    Take ol guy's advice!!!!! He knows his shit!!!! NO!!! (Which I took as meaning don't lean it out, fat is good), am I right???
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    All I am doing is trying to do is fine tune it for idle. Power mixture is where I want it. 1,7,4and 6 are very rich at idle only, they are also on the same side of the carb since I am running a dual plane intake. I have to idle it quite a long time since the no wake zone is almost a half mile long. seems like it should be idle mixture on one side of the carb only.

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    Senior Member Brendellajet's Avatar
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    Since its a QFT carb Im going to assume that it has 4 idle mixture screws? Have you adjusted them? A general rule of thumb will be to open each of them up until the RPM's stop increasing. Watch the tach. Sometimes the effect is subtle, but you do all 4 (I like to go around twice) and that could help...

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    Quote Originally Posted by ol guy View Post
    NO!!! M

    If he is runing rich at idle (and seems to have a good understanding of the dual plane manifold), why shouldn't he lean it out????

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    Idle mixture has no correlation to main metered mixture. Yes, adjust your idle mixture to be correct. It will not alter your main circuit power mixture at all.
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    Quote Originally Posted by Brendellajet View Post
    Since its a QFT carb Im going to assume that it has 4 idle mixture screws? Have you adjusted them? A general rule of thumb will be to open each of them up until the RPM's stop increasing. Watch the tach. Sometimes the effect is subtle, but you do all 4 (I like to go around twice) and that could help...
    I nailed the mixture on the second try, kinda a pain when on the idle since the lake is 4600 feet and I live at 6600. I'll go around again but just needed an opinion to make sure my thinking was right , Thanks.

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    Quote Originally Posted by Warp Speed View Post
    If he is runing rich at idle (and seems to have a good understanding of the dual plane manifold), why shouldn't he lean it out????
    Thanks for getting it I may sometimes sound like a tard on this sight, but I kinda know what I am doing just like to get opinions.

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    Quote Originally Posted by jungledave View Post
    I nailed the mixture on the second try, kinda a pain when on the idle since the lake is 4600 feet and I live at 6600. I'll go around again but just needed an opinion to make sure my thinking was right , Thanks.
    Bingo! They are so complicated!

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