setting air/fuel screws on Holley carb. - CorvetteForum - Chevrolet Corvette Forum Discussion

Register FAQ Search Today's Posts Mark Forums Read Vendor Directory

C3 Tech/Performance
V8 Technical Info, Internal Engine, External Engine, Basic Tech and Maintenance for the C3 Corvette

setting air/fuel screws on Holley carb.

Reply
 
 
 
Thread Tools Search this Thread
Old 05-12-2002, 05:53 PM   #1
candyapplevette
CF Senior Member
Thread Starter
 
Member Since: Apr 2002
Location: Ringgold GA
Posts: 121
Thanks: 0
Thanked 0 Times in 0 Posts
Default setting air/fuel screws on Holley carb.

What is the correct way to set and adjust the air/fuel screws on a Holley 750 double pumper with the 4 corner idle system?
I have been told by some local people to set all 4 screws the same and I have also been told to set the back ones approx. 1/8 to 1/4 turn out only.
What is the proper way to set this carburator? All of the Holley's I used to run were the old style with 2 air/fuel screws.

Thanks
candyapplevette is offline   Reply With Quote
Old 05-12-2002, 06:18 PM   #2
Larry B.
CF Senior Member
 
Larry B.'s Avatar
 
Member Since: Sep 2000
Location: Orlando Floriduh
Posts: 5,638
Thanks: 0
Thanked 0 Times in 0 Posts
Default Re: setting air/fuel screws on Holley carb. (candyapplevette)

Just adjust them for the smoothest idle or if you have a vacuum gage then obtain the highest vacuum reading. ;)
Larry B. is offline   Reply With Quote
Old 05-14-2002, 04:01 PM   #3
norvalwilhelm
CF Senior Member
 
norvalwilhelm's Avatar
 
Member Since: Nov 2000
Location: Waterloo ontario Canada
Posts: 11,876
Thanks: 0
Thanked 0 Times in 0 Posts
Default Re: setting air/fuel screws on Holley carb. (candyapplevette)

All the holleys I have delt with idle too rich. I usually have a healthy cam so it doesn't help. I always drill about .100 hole in each of the throttle plates. The placement is important. I then install a .015 wire in each of the idle circuit passageways. You are trying to establish 1 1/2 turns out from bottoming the idle screws. This is where they are ment to be. If they are almost closed to get a descent idle something is not right. The throttle plates should also be closed. Too open and the transferr slots start adding to the idle mixture. I the throttles are uncovering the transferr slots the idle screws will be insensitive.
I set front and back the same. Try for the best idle at around 1 1/2 turns.
norvalwilhelm is offline   Reply With Quote
Old 05-14-2002, 07:42 PM   #4
MotorHead
CF Senior Member
 
MotorHead's Avatar
 
Member Since: Apr 2000
Location: Who said "Nothing is impossible" I've been doing nothing for years.
Posts: 17,271
Thanked 75 Times in 62 Posts
Default Re: setting air/fuel screws on Holley carb. (norvalwilhelm)

First I turn all screws 1 1/2 turns out then get the vacuum gauge and since I only have two hands I set the primary first then the secondary :D


[Modified by MotorHead, 5:43 PM 5/14/2002]
MotorHead is offline   Reply With Quote
Old 05-14-2002, 08:31 PM   #5
clem zahrobsky
CF Senior Member
Cruise-In I Veteran
Cruise-In II Veteran
 
clem zahrobsky's Avatar
 
Member Since: Mar 1999
Location: delmont pa
Posts: 6,744
Thanks: 0
Thanked 0 Times in 0 Posts
Default Re: setting air/fuel screws on Holley carb. (candyapplevette)

take the carb off the engine,set the idle speed screw so only .040 of the idle transfer slot is showing. set the butterflys on the secondary side to be open the same amount. install the secondary stop screw in upside down so you can turn it from the top. put the carb back on and if it does not idle fast enought take it of and drill all 4 butterflys with a 3/32" drill about 5/16" of a inch from the edge,centered towards the outside edge of the butterflys. all DP are very rich on idle and you can put the wire into the IFR or solder them up and redrill them smaller :chevy
clem zahrobsky is offline   Reply With Quote
Go Back   CorvetteForum - Chevrolet Corvette Forum Discussion >
Reload this Page
  • setting air/fuel screws on Holley carb.
  •  
     
    Reply

    Related Topics
    Thread Thread Starter Forum Replies Last Post
    Air/Fuel Mixture Brumbach C1 & C2 Corvettes 7 07-04-2015 12:41 PM
    Holley Street Avenger - High Idle Issue SharkAttack C3 Tech/Performance 21 05-23-2015 09:31 PM
    Nitrous Air/Fuel Help Please!!!! my01corvette C5 Forced Induction/Nitrous 19 04-07-2015 09:19 AM
    Ideal Air/Fuel Ratio For Stock '02 C5 Z06 LS6 Engine? Z06 Whisperer Autocrossing & Roadracing 5 04-04-2007 08:59 AM
    Can you easily change Air/Fuel ratio? TheHammer C5 General 13 03-12-2005 11:26 PM


    Tags
    air, airfuel, c3, carb, corner, corvette, fuel, holley, idle, number, performance, ratio, screws, setting, settings, terms, turns

    Thread Tools Search this Thread
    Search this Thread:

    Click for Advanced Search

    Posting Rules
    You may not post new threads
    You may not 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 Off
    Pingbacks are Off
    Refbacks are Off

    Forum Jump


    All times are GMT -4. The time now is 04:42 AM.