my car is hard to start, and when it does start it idles rough between 300rpm n 500rpm and slowly gains rpm over 30 seconds to 800 rpm thne is fine. if i punch the throttle to the floor the car trys to die, or sumtimes falls to bout 300rpm and then rapidly picks up to 4k rpms or higher. if i slowly put my foot into the throttle it piks up fine. is this a mixture screw problem with my carb or something else?

i have no vacuum leaks that i can tell, my vacuum advance is set up on driver side port for FULL vacuum. i have a cheap off the shelf inline fuel pump that puts out about 7lbs of pressure, i have a regulator set on 4 1/2 lbs of pressure. i was told not to set it over 5lbs of pressure. anyone have any ideas?

 

Remove it and clean it, that's an old piece, I'd run 5lbs.psi myself.....

 

its bran new lol

 

You followed all the instructions in the manual for setting the float height, installing and tuning?

 

these carbs are virtually fool proof HOWEVER they are not emissions compliant!! if the laws in your area are such that you can run this carb,i would begin with a careful rebuild,THEN i would run a holley blue FP regulated to 7 lbs fuel pressure,check the VOLUME of fuel too it should produce 1 pint in thirty seconds for satisfactory results

 

My mistake, thought you had an original carb on there... Brock/ Edelbrock, duh, what can I say, I run a Holley....

 

ya thankin i shulda ran holley too. but already got this brock so ima stick wit it. its new but the mixture screws got messed with, so did the idler screw, and the mechanic still didnt fix my hesitation, said he didnt know, couldnt figure it out... no charge have a nice day. lol so im tryin to adjust myself. i needa buy a timing lite i know and just go over everything myself again. just getting fed up with this car.... blah. oh well keep pushin thro!

 

They are easy to tune, do you have the manual / instructions, if not you can download it. Like it was said above they are almost foolproof. Unfortunately there are alot of mechanics out there nowadays who don't know chit about carbs....