carb tuning

[72velle]

i have a 4 barrel edelbrock carb sitting on a 350 right now. i have a question on the two screws in front of the carb. i am trying to get the carb tuned just right. i was told that if you screw them in all the way then unscrew 1-1/4 turns out, its good. i tried that and the car wasnt getting enough fuel. i have got them about 4 turns out now. is there a certain amount of turns it should be? or is it just trial and error. the car runs strong right now. but if i could get it to run better through better tuning, i will. thanks. gotten a lot of help from here.

[molhannah]

Those are the idle mixture screws, with engine at operating temperature and idle cams off, slowly turn one screw in until idle drops, then back it off until you get the highest idle from that screw. Now do the next one the same way, after you have achieved the higher idle readjust the idle stop screw to about 700 RPM, slightly higher for a automatic. Hope this helps.

[slipknot_me]

Adjust your carb with a vaccuum guage. Turn the idle mixture screws all the way in then back them out 1 1/2 turns. Attach your vac guage to manifold vac. Theres a port at the base of your carb, in front. Warm the engine to operating temp and prop open the choke all the way. Then adjust the screws in equal amounts until you get the highest vac reading.

keith

[72velle]

thanks how much is a vacuum gauge?

[MagicRat]

Originally Posted by slipknot_me

Adjust your carb with a vaccuum guage. Turn the idle mixture screws all the way in then back them out 1 1/2 turns. Attach your vac guage to manifold vac. Theres a port at the base of your carb, in front. Warm the engine to operating temp and prop open the choke all the way. Then adjust the screws in equal amounts until you get the highest vac reading.

keith

yup, that's how I do it.
Usually a basic vacuum gauge is about $10-30