Quadrajet a/f mixture screw setting - Hot Rod Forum : Hotrodders Bulletin Board
Hotrodders.com -- Hot Rod Forum



Register FAQ Search Today's Posts Unanswered Posts Auto Escrow Insurance Auto Loans
Hot Rod Forum : Hotrodders Bulletin Board > Tech Help> Engine
User Name
Password
lost password?   |   register now

Reply
 
LinkBack Thread Tools
  #1 (permalink)  
Old 07-05-2007, 11:53 AM
Registered User
 
Join Date: Jun 2007
Location: florida
Posts: 7
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
Quadrajet a/f mixture screw setting

I am having trouble setting up my quadrajet on a 74 L-82 (350) vette. how many turns out should i start at on the mixture screws? and how do i go about tuning it from there? I do have a vacuum gauge but am not sure what to look for. anyone good at this?

    Advertisement
Reply With Quote Quick reply to this message
Sponsored Links
Advertisement
 
  #2 (permalink)  
Old 07-05-2007, 12:54 PM
solidaxel's Avatar
Member
 

Last journal entry: Project garage complete!
Last photo:
Join Date: Jul 2003
Location: So. Arizona
Posts: 558
Wiki Edits: 0

Thanks: 2
Thanked 1 Time in 1 Post
I place the vacuum gauge on a constant source on the carb and set the idle so it will run, then adjust one screw at a time until you reach the highest reading. Lower the idle until until you have about 700rpm then adjust the screws until you get the highest reading again (should be running smooth!) now turn up the idle to specs and place in gear with foot on brake, should still be smooth.
Try that and tell what you get!!
Reply With Quote Quick reply to this message
  #3 (permalink)  
Old 07-05-2007, 01:56 PM
DoubleVision's Avatar
Not Considered a Senior Member
 
Last photo:
Join Date: Oct 2002
Location: Heart Of Dixie
Age: 40
Posts: 10,654
Wiki Edits: 0

Thanks: 15
Thanked 58 Times in 55 Posts
Solid nailed it.
Reply With Quote Quick reply to this message
  #4 (permalink)  
Old 07-05-2007, 08:11 PM
Member
 
Last photo:
Join Date: May 2003
Location: Shreveport LA
Age: 64
Posts: 5,103
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
Start with the screws about 3 turns out from bottomed, maybe 4, and be sure you don't screw them down tight when you bottom them. The metal in there is kinda fragile.
Reply With Quote Quick reply to this message
  #5 (permalink)  
Old 07-05-2007, 08:15 PM
Registered User
 
Last photo:
Join Date: Jul 2007
Location: Ankeny IA
Posts: 39
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
Quote:
Originally Posted by solidaxel
I place the vacuum gauge on a constant source on the carb and set the idle so it will run, then adjust one screw at a time until you reach the highest reading. Lower the idle until until you have about 700rpm then adjust the screws until you get the highest reading again (should be running smooth!) now turn up the idle to specs and place in gear with foot on brake, should still be smooth.
Try that and tell what you get!!
Your on it! It will take some time. You want the highest vacuum you can get.

Mark.
Reply With Quote Quick reply to this message
  #6 (permalink)  
Old 07-06-2007, 08:58 AM
Registered User
 
Join Date: Jun 2007
Location: florida
Posts: 7
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
Thank you for helping now i guess its up to me to get it right. after the screws have been turned in how far can i expect them to have gone? (just for reference) and when you say one at a time does that mean i work only the left until the vacuum is high befor switching to the right, or alternate between the screws giving them each only a 1/4 turn or so then going to the next. i know i am a pain but i really want to nail this. Thanks again
Reply With Quote Quick reply to this message
  #7 (permalink)  
Old 07-06-2007, 09:13 AM
Registered User
 
Last photo:
Join Date: Jul 2007
Location: Ankeny IA
Posts: 39
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
Quote:
Originally Posted by silversurfer74
Thank you for helping now i guess its up to me to get it right. after the screws have been turned in how far can i expect them to have gone? (just for reference) and when you say one at a time does that mean i work only the left until the vacuum is high befor switching to the right, or alternate between the screws giving them each only a 1/4 turn or so then going to the next. i know i am a pain but i really want to nail this. Thanks again
Yep. Alternate. Go from one to the other, It takes some time. When you get the highest vacuum on one side go back to the other and so on. Good luck.

Mark.
Reply With Quote Quick reply to this message

Recent Engine posts with photos

Quick Reply
Message:
Options

Register Now

In order to be able to post messages on the Hot Rod Forum : Hotrodders Bulletin Board forums, you must first register.
Please enter your desired user name (usually not your first and last name), your email address and other required details in the form below.
User Name:
If you do not want to register, fill this field only and the name will be used as user name for your post.
Password
Please enter a password for your user account. Note that passwords are case-sensitive.
Password:
Confirm Password:
Email Address
Please enter a valid email address for yourself.
Email Address:

Log-in

Human Verification

In order to verify that you are a human and not a spam bot, please enter the answer into the following box below based on the instructions contained in the graphic.




Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Thread Tools

Posting Rules
You may post new threads
You may post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On


Similar Threads
Thread Thread Starter Forum Replies Last Post
A/F idle mixture ?? voodoosurfer Engine 3 10-28-2005 10:47 AM
I'm going to make a bonfire out of my car blown69stang Engine 36 08-22-2005 03:36 PM
QJet Initial Idle Mixture Setting JohnTN Engine 4 06-10-2005 01:31 PM
Idle Mixture Screw Plugs kringold Engine 1 05-10-2005 04:07 PM
Holly mixture adjusting screw FASTMONTE Engine 3 02-05-2004 07:38 AM


All times are GMT -6. The time now is 11:46 AM.


Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2014, vBulletin Solutions, Inc.
Search Engine Optimization by vBSEO 3.6.0 PL2
Copyright Hotrodders.com 1999 - 2012. All Rights Reserved.