tune help

okey i drilled the secondaries with 3mm holes. now my mixture screws work! but i have another problem... now when i pump the gas the rpm stays high for like 5seconds before coming back down. tried to find vac leak and even did new carb and spacer gasgets. could too big drilled holes cause rpm to hang? And when i but my hand over air horn the rpm raises EDIT: i riveted the drilled holes back and the car runs like it used to