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-   -   One Idle Mix Screw Not Working!!! (

GUITAR1989 10-05-2012 01:56 AM

One Idle Mix Screw Not Working!!!
Hey guys :) Im having some trouble with my Edelbrock 1406 carb. My drivers side idle mixture screw has no effect. I checked the Edelbrock dvd and it says to spray compressed air into the idle mixture screw hole. My trucks actually up at my moms house at the moment so I havent had a chance to try and put air through the screw hole yet. Will compressed air unclog the circuit no matter where the debris is? or will it only push junk outta the little hole the mixture screw tip goes into?

Any tips or suggestions are welcome about cleaning it or checking for other possible problems. You probably know alot more than I do about carbs :P

-I dont think its a vac leak cause vac is stable at 15
-Ive done a good amount of searching for vacuum leaks and replaced vac componants
-floats are at correct lvl
-My plugs are also black and sooty isnt a vac leak suppose to lean out the engine so the plugs wouldnt be black right?
-only drivers side mixture screw has no effect the passenger side is working.

Thanks for reading guys

75gmck25 10-05-2012 06:08 AM

It's easy to remove the screw and use one of the cans of compressed air to blow through it, but it might not remove debris that's really stuck. Its also easy to unscrew the jets to give it a good exit path, and then blow air through from that side also.

If you are running rich I would try another check also. Use a flashlight and a small mirror at an angle to look down into the carb while its running. If you see any evidence of raw fuel dribbling on one side, there is probably something plugging the venturi on that side and making it run rich. This obstruction (which might be something sucked in when you had the air cleaner off) reduces air flow and makes it run rich. It usually means you also have to raise the idle to keep it running.


RWENUTS 10-05-2012 01:23 PM

Hook your vacuum advance up to manifold vacuum, turn down your idle. You've uncovered the idle transition slot too much with a high idle. Runs rich cause you're starting to run on the power circuit.

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