Holley Idle mixture question..
Thread Starter
Team Owner
Joined: Jul 2001
Posts: 182,997
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From: Lakeland, FL
Cruise-In IV-V-VI-VII-VIII Veteran
St. Jude Donor '03, '06, '17
Holley Idle mixture question..
How do I adjust the idle mixture leaner... Do I have to turn the idle mixture screws left or right to get a leaner idle mixture?
:cheers:
Olivier
:cheers:
Olivier
Drifting
Joined: Oct 2001
Posts: 1,699
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From: Westampton NJ
Re: Holley Idle mixture question.. (GrandSportC3)
Depends on the carb. Whichever way backs the screws out of the seats is richer. The way to set it is to first screw them in until they LIGHTLY touch the seats. Then back them out 1 to 1 1/2 turns. Check your idle mixture with the engine hot.
Race Director
Joined: Nov 2000
Posts: 11,872
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From: Waterloo ontario Canada
Re: Holley Idle mixture question.. (GrandSportC3)
Holley idle screws are meant to be set at 1 1/2 turns. Sure there are fine adjustments but they should end up about there. With a hotter cam you might have to drill 1/8th holes in the butterflies that have accelerator pumps. A double pumper gets 4 holes. They must also be drilled on the side that forces you to hold the throttles closed while drilling. If you can just turn the carb upside down and drill they are on the wrong side of the shaft.
You can also do the .015 wire trick to the idle hole to lean out the mixture.
If you screw the screws in or clockwise nearly all the way to lean it out you should be doing something else, like the holes and wire in the circuit.
You can also do the .015 wire trick to the idle hole to lean out the mixture.
If you screw the screws in or clockwise nearly all the way to lean it out you should be doing something else, like the holes and wire in the circuit.
Safety Car
Joined: Sep 2000
Posts: 4,679
Likes: 6
From: Charles Town WV
Re: Holley Idle mixture question.. (norvalwilhelm)
Holley idle screws are meant to be set at 1 1/2 turns. Sure there are fine adjustments but they should end up about there. With a hotter cam you might have to drill 1/8th holes in the butterflies that have accelerator pumps. A double pumper gets 4 holes. They must also be drilled on the side that forces you to hold the throttles closed while drilling. If you can just turn the carb upside down and drill they are on the wrong side of the shaft.
You can also do the .015 wire trick to the idle hole to lean out the mixture.
If you screw the screws in or clockwise nearly all the way to lean it out you should be doing something else, like the holes and wire in the circuit.
You can also do the .015 wire trick to the idle hole to lean out the mixture.
If you screw the screws in or clockwise nearly all the way to lean it out you should be doing something else, like the holes and wire in the circuit.
Thread Starter
Team Owner
Joined: Jul 2001
Posts: 182,997
Likes: 88
From: Lakeland, FL
Cruise-In IV-V-VI-VII-VIII Veteran
St. Jude Donor '03, '06, '17
Re: Holley Idle mixture question.. (rainman69)
Depends on the carb. Whichever way backs the screws out of the seats is richer. The way to set it is to first screw them in until they LIGHTLY touch the seats. Then back them out 1 to 1 1/2 turns. Check your idle mixture with the engine hot.
Currently - the idle is set to 1200 RPM when cold... When the car gets above 195 degrees - the idle drops to 900... sometimes the engine even floods... :( :( :(
:cheers:
Olivier
Thread Starter
Team Owner
Joined: Jul 2001
Posts: 182,997
Likes: 88
From: Lakeland, FL
Cruise-In IV-V-VI-VII-VIII Veteran
St. Jude Donor '03, '06, '17
Re: Holley Idle mixture question..
I actually have 4 corner idle on my carb... So - if I understand correctly - I have to screw all 4 idle adjustment screws completely inside and then 1 1/2 turns out.. right???
Thanks!!
:cheers:
Olivier
Thanks!!
:cheers:
Olivier
Pro
Joined: Oct 2001
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Re: Holley Idle mixture question.. (GrandSportC3)
Right. Clockwise gently until they seat, then back out 1.5 turns. This is a good starting point. I like to run the idle a bit lean to reduce fouling.
Mine right now are only 3/4 of a turn out, but this is a 4150HP carb which may be a bit different. I do have the holes in the butterflies.
Mine right now are only 3/4 of a turn out, but this is a 4150HP carb which may be a bit different. I do have the holes in the butterflies.
Race Director
Joined: Nov 2000
Posts: 11,872
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From: Waterloo ontario Canada
Re: Holley Idle mixture question.. (Steve Straus)
Steve Straus you can open the secondaries a little but in this case it would cause the transfer slots to be uncovered which screws up the idle circuit. You need to close the throttle enough to prevent fuel from being drawn from the transfer slots. In this case the , start at .100 in you like holes in the throttle plates which allow the throttles to be closed protecting the transfer slots. If this still isn't enough the wire in the idle circuit is needed. Holley even sells throttle plates with the holes already drill but you can do your own. Holley also recommends the wire in the idle circuit.
If you need to close the idle needles off almost completely to get the car to idle you need to do something and that something is close the transfer slots. They are being exposed.
If you need to close the idle needles off almost completely to get the car to idle you need to do something and that something is close the transfer slots. They are being exposed.
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Melting Slicks
Joined: Oct 2001
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From: Halifax, Nova Scotia, Canada
Re: Holley Idle mixture question.. (norvalwilhelm)
With a hotter cam you might have to drill 1/8th holes in the butterflies that have accelerator pumps.
You can also do the .015 wire trick to the idle hole to lean out the mixture.
You can also do the .015 wire trick to the idle hole to lean out the mixture.
