carb question
Thread Starter
Melting Slicks
Joined: Dec 2000
Posts: 2,629
Likes: 7
From: Lawrenceville PA
carb question
My car idles at around 400 rpm in drive and I need to adjust the idle speed but I don't know which screw on my Carter Quadrajet is the idle speed screw. Is there any easy way to determine the idle speed screw? There are several screws on the carb that it could be, and in my ignorance I can't figure out which one it is. Any help would be appreciated. :bb
Melting Slicks
Joined: Oct 2000
Posts: 3,023
Likes: 2
From: TEXASTEXASTEXASTEXAS TEXASTEXASTEXASTEXAS
St. Jude Contributor
Re: carb question (midget)
A Carter? What year? I know some midyears had Carters, but I didn't know any C3s did.
Wish I could tell you where the idle mixture screws are, but I've never messed with a carter. Probably two screws, probably in the throttle plate, but someone else here will know.
[EDIT: on second thought, Carter didn't make Qjets, Rochester did. Do you mean a Rochester Quadrajet? If so, what year? My '69 has idle mixture screws in the front of the throttle plate and an idle adjusting screw on the forward drivers' side of the carb that screws in and out to limit how far the throttle can go back.]
JB
[Modified by JB, 8:23 PM 7/1/2002]
Wish I could tell you where the idle mixture screws are, but I've never messed with a carter. Probably two screws, probably in the throttle plate, but someone else here will know.
[EDIT: on second thought, Carter didn't make Qjets, Rochester did. Do you mean a Rochester Quadrajet? If so, what year? My '69 has idle mixture screws in the front of the throttle plate and an idle adjusting screw on the forward drivers' side of the carb that screws in and out to limit how far the throttle can go back.]
JB
[Modified by JB, 8:23 PM 7/1/2002]
Le Mans Master
Joined: Sep 2000
Posts: 5,635
Likes: 4
From: Orlando Floriduh
Re: carb question (midget)
Yes. Carter did make some Quadra-jets under contract from Rochester. They are exactly like Q-jets except the "carter" name. The normal Idle speed screw is on the driver's side near the arm that the throttle cable hooks to. It directly moves the arm. turning the screw clockwise (in) should increase the idle speed.
Team Owner
Joined: Jul 1999
Posts: 26,545
Likes: 46
From: Huntersville NC
Re: carb question (JB)
Follow the instructions above and you should be OK. On the other hand, if you look at the illustration in my Haynes manual, the labels for the mixture screws and the idle speed screws are mixed up!!! :mad
Very confusing for me as a newbie!! MJ
[Modified by MNJack, 9:27 PM 7/1/2002]
Very confusing for me as a newbie!! MJ
[Modified by MNJack, 9:27 PM 7/1/2002]
Pro
Joined: May 2002
Posts: 726
Likes: 0
From: Petaluma CA
Re: carb question (MNJack)
Don't ya just hate that. My favorite pet peeve is when the books call the same thing by three different names. As a teenager, all I had to learn from was books. With crappy old cars, rusted up, one Chiltons (probably for the wrong year)......and no forum !!! :seeya
Follow the instructions above and you should be OK. On the other hand, if you look at the illustration in my Haynes manual, the labels for the mixture screws and the idle speed screws are mixed up!!! :mad
Very confusing for me as a newbie!! MJ
[Modified by MNJack, 9:27 PM 7/1/2002]
Very confusing for me as a newbie!! MJ
[Modified by MNJack, 9:27 PM 7/1/2002]
Burning Brakes
Joined: Mar 2002
Posts: 803
Likes: 0
From: South San Francisco CA
Re: carb question (midget)
The idle speed is generally a "stop" and can be located by pressing the gas pedal and watching the throttle cable. As the cable moves and then returns to its original point, there is a screw that can be turned in (to raise) or out (to lower) the amount of throttle cable movement. Turn that screw one half turn clockwise and see if your idle speed increases. If nothing happens...you've got the wrong screw. Hint:* The screw usually has a pretty big head on it.
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Burning Brakes
Joined: Aug 1999
Posts: 774
Likes: 0
From: Palatine IL
Re: carb question (midget)
The idle speed adjustment on my Q-jet carb is on the drivers side, toward the front of the carb, with a small spring around it.
[Modified by vettesite, 1:05 PM 7/2/2002]
[Modified by vettesite, 1:05 PM 7/2/2002]
Le Mans Master
Joined: Mar 1999
Posts: 6,744
Likes: 1
From: delmont pa
Cruise-In I Veteran
Cruise-In II Veteran
Re: carb question (Neo Fender)
that is the fast idle when the choke is on adjustment screw if you set the curb idle with that you must not have a working choke :chevy
