Hot Rod Forum : Hotrodders Bulletin Board

Hot Rod Forum : Hotrodders Bulletin Board (
-   Hotrodding Basics (
-   -   edelbrock mixture screw (

fast68 01-12-2011 03:22 PM

edelbrock mixture screw
got an edelbrock 4bbl on an old sbc

with it running the pass side screw can be screwed all the way in and the engine doesnt stumble or anything

but it does stumble when the driver side screw is turned in

what does this mean?

also the pass side exhaust has a bad rotten leak at the shorty header collector in which is what we have the truck here to fix already anyways

has something to do with that maybe?

how do you properly set the mix screws on these carbs?

can i use our vacuum guage?

bigdog7373 01-12-2011 03:57 PM

Well, the header leak may have some impact on it because that bank of cylinders has less exhaust restriction and in turn makes slightly more power which means it needs more fuel. Fix it and see what happens.

spinn 01-16-2011 01:57 PM

The manual has the best instruction for tuning the edelbrock afb. Follow it and it will work well.

about 1.5-2 turns out . Make sure the engine dies with the ides screws all the way in. If not it is pull past the idle ports. The screws only effect idle mixture. Nothing else.

The exhaust leaks must be fixed .

cucumber1949 01-16-2011 08:34 PM

Also check to make sure the mixture screw and seat are not contaminated with dirt which may be keeping the mixture screw from closing all the way. If you suspect this check out the following from the Edelbrock website.

1971BB427 01-17-2011 09:28 AM

A couple things can cause the mixture screw to not affect idle. It could have a vacuum leak, or it could be a worn seat in that side and it's still flowing with the screw all the way in. Try gently seating it with a little pressure, then back it out a couple turns and see if that helps.
Check for leaks around the carb with starting fluid sprayed at the base to see where it might be sucking air.

All times are GMT -6. The time now is 01:23 PM.

Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2017, vBulletin Solutions, Inc.
Search Engine Optimization by vBSEO 3.6.0 PL2
vBulletin Security provided by vBSecurity v2.2.2 (Pro) - vBulletin Mods & Addons Copyright © 2017 DragonByte Technologies Ltd.
Copyright 1999 - 2012. All Rights Reserved.