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I have a 600cfm Holley on my car - 64.5 / 289 / Auto.I have the idle screw on the base removed and have tried adjusting the 2 screws on the metering block and still have a high idle on the car which I can`t change.Any Suggestions ??
**checked the butterflys - seem to be closed.Gas leak thru the carb.??Car runs fine just idles high.Thanks
 

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If the butterflies are closing, it should be idled down. Gas leaking into the carb would cause it to die unless there is enough air to keep it running. Sounds like a vacuum leak around the base of the carb.
 

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Make sure your secondaries are closed. There is a screw that is almost impossible to get to to adjust them. You don't want them completely closed - but almost.
 

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heck out what the previous posts say..if that is all ok, drill a 3/64" hole in the bottom butterflies to allow more air in...that should cure it! an ol Holley trick from days gone by
 

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I have the idle screw on the base removed

Please explain. Are you saying you've completely unscrewed the primary idle speed screw? The engine should die.

Verify that the primary and secondary butterflies are completely closed. A bent throttle shaft can keep the butterflies from closing.

Check for vacuum leaks around the carb and intake manifold. Check alignment and coverage of carb spacer/gaskets, if so equipped. Verify freedom of movement of butterfles within spacer.

Try plugging PCV hose/port. Report results.

Get back to us...
 

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Ooooooooo...I missed that about the screws being compleely out!!!!!!!!!!!
 
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Discussion Starter #9
At the base of my carb there is a screw to adjust idle ? where the pedal linkage connects (this is completely removed).The butterflys are closed.Checked timing - O.K. Checked float levels O.K.Will check for Vacuum leak.Thanks
 

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At the base of my carb there is a screw to adjust idle ?

Primary idle speed screw is located below the linkage attachement, on the baseplate, driver's side.

Also, if equipped with automatic choke, check fast idle screw and cam operation adjacent to choke controls on passenger side adjacent to primary throttle shaft.
 
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