Holley 80457-2 stumble

Check the float level,adjust as necessary. Pull the sight plug,engine running. Fuel should be right at the bottom,of the hole. Step 2: do the a/f mixture screws respond to adjustment? If not,turn the screws in.Count and mark,side to side.Seat the screws,remove them all the way.Take a rubber tipped blow gun.Shove it in the mixture screw hole,blast it with air.Do both sides.Seat the screws back in,back them out to the marked settings from before.If it still doing it. Time to tune the accelerator pump circuit. This is assuming the timing is close to where it was before,good luck