Sunday, January 1, 2012

What do the two screws on an edelbrock carb do?

I have an edelbrock 1405 on a chevy 350. I know the screw on the far right on the linkages is for the idle, and the two screws to the left are to control the fuel to air mixture, but which is air and which screw is for fuel? Or is one low end speed and the other a high end speed screw? which is which? I want to get as close to a 14.7/1 air/fuel mix.|||Consult Edelbrock or Summit Racing|||the 2 side by side are idle fuel mixture screws... higher speeds are contolled by needles/jets|||Both screws on the front of the carb are air mixture screws. There is one for each venturi. Both screws need to be adjusted equally for optimal performance|||Both screws on the front are idle air mixture. Has nothing to do with the carb after you get off the idle circet.





To adjust them rigtht, you need a vac gauge. Hook vac gauge up to full vac port (driver's side of carb)





Turn each screw till you get the highest vac reading. Do one, then readjust idle speed if needed, and then adjust the other screw to gain highest vac.. Reset idle if needed.. Them try to 'trim' up each screw to see if you can get any higher vac reading.





To set the air/fuel mixture when driving you must change metering rods and / or jets.

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