idle screw - The 1947 - Present Chevrolet & GMC Truck Message Board Network

pokethesmot · 03-19-2009, 09:12 PM

i have 2 idle screws so witch one do i turn/witch way do i turn it to make my truck idle higher

flamingbig10 · 03-19-2009, 09:46 PM

if you have a quadra jet its the one by the throttle cable

pokethesmot · 03-19-2009, 10:08 PM

yeah i got a Qjet but now witch way do i turn it

willett · 03-19-2009, 10:09 PM

turn the truck on and play with it!

pokethesmot · 03-19-2009, 10:23 PM

well what does the other screw do

enaberif · 03-19-2009, 10:48 PM

Quote:

Originally Posted by pokethesmot

well what does the other screw do

2 on the front are mixture screws to run the truck leaner or richer.
Idle screw is by throttle cable.

pokethesmot · 03-19-2009, 11:01 PM

awsome how do i tune the fuel mixture with the screws

schoolfire · 03-20-2009, 12:02 AM

Quote:

Originally Posted by pokethesmot

awsome how do i tune the fuel mixture with the screws

Counterclockwise for richer clockwise for leaner. With the idle screw counterclockwise is slower clockwise is faster.

enaberif · 03-20-2009, 01:10 AM

Quote:

Originally Posted by schoolfire

Counterclockwise for richer clockwise for leaner. With the idle screw counterclockwise is slower clockwise is faster.

And you want the mixture screws to be turned the same or relatively close.

rick1956 · 03-20-2009, 07:35 AM

If your carb has two screws on the throttle linkage (I'm being generic here), one of them is for regular idle speed and one of them is for fast idle.
The fast idle screw (controlled by your choke) is the one that has the step cam that engages against it.

73chevyman · 03-21-2009, 06:56 PM

really don't want to play with the mixture screws. there a pain to get them right. before you do any messing with them turn them to the right till it stops and count how many turns. don't tighten them up just till it stops with no butt behind it make a note for each screw. then turn them both to 3/4 to 1 1/2 turns to the left thats around about your happy medium. if you get them not right your gas milage will go in the toilet. do all your carb adjustment at running temp. i typically do 3/4 turn on both and hold my hand over the primaries if it races its to lean if it does nothing your in the ball park.. good luck

xbanone · 03-21-2009, 07:44 PM

BEFORE YOU TOUCH ANYTHING ON YOUR CARB! go buy a cheap vacuum gauge and tach learn how to use them to tune your carb. Just google search "carb tuning vacuum gauge" and follow instructions. It's not hard to do and its the only way short of using an Air/Fuel sensor to set everything up properly.

powerdriver 1958 · 03-21-2009, 08:21 PM

have adjusted by screwing the jets in until engine speed slows then back out untill best idle

enaberif · 03-21-2009, 09:09 PM

^ Good pictures.

I don't have screws for my jets.. I have this weird rectangular screws that I require to use some funky needle nose pliers to adjust!

03-19-2009, 09:12 PM	#1
pokethesmot profeshinaly unimployed Join Date: Dec 2008 Location: hazlehurst, GA Posts: 1,232	idle screw i have 2 idle screws so witch one do i turn/witch way do i turn it to make my truck idle higher __________________ my ride click here my myspace "having mud flaps is like asking for a smaller trophy"

03-19-2009, 09:46 PM	#2
flamingbig10 6.0 powered square Join Date: Feb 2008 Location: Mesquite texas Posts: 3,459	Re: idle screw if you have a quadra jet its the one by the throttle cable __________________ Aaron 1980 c-10 short bed lowered, cammed 6.0, 4l80e 3600 stall, smp tune, wilwoods, and flames best time so far best et 7.86 @87 on motor 7.57 90 on a 75 shot Build http://67-72chevytrucks.com/vboard/s...d.php?t=283326

03-19-2009, 10:08 PM	#3
pokethesmot profeshinaly unimployed Join Date: Dec 2008 Location: hazlehurst, GA Posts: 1,232	Re: idle screw yeah i got a Qjet but now witch way do i turn it __________________ my ride click here my myspace "having mud flaps is like asking for a smaller trophy"

03-19-2009, 10:09 PM	#4
willett Another Day, Another Dollar Join Date: Nov 2008 Location: North Vancouver, BC Posts: 1,316	Re: idle screw turn the truck on and play with it! __________________ -78 K20 Cheyenne 454 long box, 4" lift, 35" MT's, '84 cab, '80 box "its hip to be square"

03-19-2009, 10:23 PM	#5
pokethesmot profeshinaly unimployed Join Date: Dec 2008 Location: hazlehurst, GA Posts: 1,232	Re: idle screw well what does the other screw do __________________ my ride click here my myspace "having mud flaps is like asking for a smaller trophy"

03-19-2009, 11:01 PM	#7
pokethesmot profeshinaly unimployed Join Date: Dec 2008 Location: hazlehurst, GA Posts: 1,232	Re: idle screw awsome how do i tune the fuel mixture with the screws __________________ my ride click here my myspace "having mud flaps is like asking for a smaller trophy"

03-20-2009, 07:35 AM	#10
rick1956 Registered User Join Date: Jan 2009 Location: Edgewood, WA Posts: 108	Re: idle screw If your carb has two screws on the throttle linkage (I'm being generic here), one of them is for regular idle speed and one of them is for fast idle. The fast idle screw (controlled by your choke) is the one that has the step cam that engages against it. __________________ I may be old, but I still enjoy the feeling of the earth rotating beneath my wheels...

03-21-2009, 06:56 PM	#11
73chevyman Registered User Join Date: Nov 2008 Location: Lusby, MD Posts: 563	Re: idle screw really don't want to play with the mixture screws. there a pain to get them right. before you do any messing with them turn them to the right till it stops and count how many turns. don't tighten them up just till it stops with no butt behind it make a note for each screw. then turn them both to 3/4 to 1 1/2 turns to the left thats around about your happy medium. if you get them not right your gas milage will go in the toilet. do all your carb adjustment at running temp. i typically do 3/4 turn on both and hold my hand over the primaries if it races its to lean if it does nothing your in the ball park.. good luck __________________ http://67-72chevytrucks.com/vboard/group.php?groupid=37 73 C10 Fleetside If it ain't a Chevy it's foreign http://hotridesmag.com/

03-21-2009, 07:44 PM	#12
xbanone Registered User Join Date: Oct 2008 Location: WV Posts: 209	Re: idle screw BEFORE YOU TOUCH ANYTHING ON YOUR CARB! go buy a cheap vacuum gauge and tach learn how to use them to tune your carb. Just google search "carb tuning vacuum gauge" and follow instructions. It's not hard to do and its the only way short of using an Air/Fuel sensor to set everything up properly.

03-21-2009, 08:21 PM	#13
powerdriver 1958 Kid's Mechanic Join Date: Nov 2006 Location: Kansas City Posts: 8,241	Re: idle screw have adjusted by screwing the jets in until engine speed slows then back out untill best idle Attached Images

03-21-2009, 09:09 PM	#14
enaberif Registered User Join Date: Jan 2009 Location: Calgary, AB Posts: 1,181	Re: idle screw ^ Good pictures. I don't have screws for my jets.. I have this weird rectangular screws that I require to use some funky needle nose pliers to adjust!

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