Here's how to find and adjust the mixture screws on your carburetor.
Note that metering-block style carbs such as Holley and Demon more often have one or 2 mixture screws in each metering block depending on the number of venturi. Also those may not be located at the bottom of the carb as in factory carburetors.
How a carburetor works, schemes and explanations
This video explains, not in too much detail, how a 28mm Walbro diaphragm
carburetor works (using mainly schemes to point out what happens inside).
It explains what occurs at the venturi, what the butterfly valve is for,
how the needle doses the amount of fuel, and how does the diaphragm slide
How To Adjust The Accelerator Pump On Holley Carburetors
How-to adjust the accelerator pump on Holley carburetors to avoid stumbling
and hesitation upon acceleration. Tips include: How to check for the
clearance between the accelerator pump diaphragm arm & operating lever;
how-to select the correct accelerator pump nozzle size, and accelerator
pump cam selection and installation. Additional information can be found on
How To Adjust The Idle Mixture Screws On Holley Carburetors
Tips on adjusting the idle mixture on Holley carburetors, using a simple
vacuum gauge. Proper idle mixture adjustments can prevent bogging,
hesitation, rough idle, backfire, stalling and hard starting. Additional
information can be found on Holley's Blog:
Auto Repair & Maintenance : How to Adjust Carburetors
Idle speed and idle mixture are the two most common adjustments made to
carburetors, and these adjustments start by warming up the vehicle to full
engine-operating temperature. Find out how to perform a lean-drop
adjustment with help from an ASE-certified master automobile technician in
this free video on carburetors.
Expert: Clark Mason
Bio: Clark Mason is an ASE-certified master automobile technician.
Filmmaker: Christian Munoz-Donoso
Setting Curb Idle Speed of Carburetor Video -Holley Carb DVD
Buy the "Holley Installation & Tuning" DVD
Holley Installation & Tuning DVD: Curb Idle Speed Screw
Here we show you how to properly adjust the curb idle speed on your Holley
carb. First find your idle RPM setting from under your hood or from a
repair manual. Turning the screw clockwise will raise the RPM's and counter
clockwise will lower the RPM's. Check and adjust until the proper setting
If you buy a brand new Holley 4-barrel, this DVD now comes in the box with
every purchase. If you already own a Holley carburetor or would like to
learn about the internals of the all-time, most popular modular style
carburetor, this is the DVD for you.
It's the ultimate installation, tuning and troubleshooting guide for the
Holley modular style carburetor. This disc will also help tune and
troubleshoot any other brand of modular style and some one-piece style
Menus are full of bonus information and detailed animated tours of
internals and accessory kits.
Get the full DVD with all of the interactive menus, detailed animated tours
of internals and accessory kits here...
Don't forget our Basic Engine Building DVD. This video is great for people
interested in car repair, car care, and restoration. As well as hot rods,
muscle cars, performance parts, and Boosting horsepower. It can also help
you to gain knowledge for increasing fuel economy, how to lower your
emissions, and covers preventative maintenance to avoid little things like
Sample clips on our YouTube page and at our store here...
BoxWrench.net is a community and resource designed for automotive
3 New Transmission DVDs and a Differential Rebuilding DVD just added.
BoxWrench on Facebook:
(3)- CARB SLOW JET ADJUST= EASY WAY
FOR OPTIMAL PERFORMANCE , THIS IS THE BEST, EASIEST UNDERSTOOD TECHNIQUE.
Slow jets or air jets are very simple and have been around for decades and
How to adjust Quadrajet/Dualjet fast idle
Quadrajet/Dualjet Rochesters have a fast idle adjustment screw that is
separate from the base idle screw.
Here's how to locate it.
Note: Ever since Charter "fixed" my internet and cable after the lightning
strike, it hasn't worked right. Go figure. So, if you see this posted then
I was finally successful in getting a video uploaded.
how to minimize engine bog with a Quadrajet carb
this is to minimize engine bog when the pedal is to the metal. do not over
tighten, very small spring...you want to try 1/4 turns or 1/2...q-jets are
good if tuned properly. also when you are tightening screw it will have
tension on it so keep the screwdriver firm. 1986 gmc sierra single
straightpipe to cherrybomb. you will need a small flathead screwdriver and
a 3/32 allen key. be sure not to tighten to much or else your vacuum
secondary flaps wont open.