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mark houghton mark houghton is offline
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Join Date: Jul 2008
Location: Central Washington State
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Originally Posted by JFairman View Post
The term "air correction screw" is another word for the idle speed fuel mixture adjustment on a carburator and it does not apply to CIS fuel injection.
You're not correcting air or adjusting mixture you are only adjusting the amount of air available at idle speed.

Weber, Solex, and Dellorto Carbs have an idle air correction or idle mixture screw for each throat along with an individual throttle butterfly stop screw or air bypass screw for setting idle speed and synchronising the individual carburator throats.
Using the wrong term for the idle speed screw is confusing to some people that have heard the term air correction screw before but are not sure what it means..

Idle speed on all fuel injected motors I've seen is controlled by bypassing air around the closed throttle butterfly and the idle speed screw changes the size of the passageway the air goes through in the process. it has NO effect on fuel mixture at idle or any other speed.

Idle mixture is adjusted by the CO adjustment screw and that's right next to the CIS fuel head and no where near the throttle body.
Yeah Jim, whip and old dog while he's down . I stand corrected on using old carb terminology (old farts have foggy brains). I just couldn't remember the exact term for the idle speed screw. "Air correction": depending on how far it's screwed in or out will affect ("correct" being a misnomer) the amount of air bypassing the TB.

Benny, sorry for adding to your confusion. Tweeking that screw is the final step to setting your idle, once everything else is adjusted correctly. The last time I had the motor out, I even went so far as to attach a long shaft to that screw...the end of which exits just left rear of the IC. I can reach back with my fingers now and adjust in a heartbeat.
Mark H. 1987 930, GP White, Wevo shifter, Borla exhaust, stock everything else. The result of a massive Pelicanite good will fire recovery effort. Truely an open book, ready for the slippery slopes to modification.
Old 06-04-2010, 07:42 PM
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