With out the make of the carb. we wouldn't know what type of idle circut adjustment you have. There are two common types, and they are both adjusted in the same fashion however. The Larger of the 2 screws is the idle rpm adjustment. When you turn it clockwise it will raise the rpm's.Turn it clockwise to slightly increase the idle. The smaller screw adjusts the idle mixture. Turn this screw 1/4-1/2 a turn counter clockwise and note the difference in rpm's. If they drop, turn back to the start position,and turn 1/4-1/2 turn past that. If they climb, continue 1/4 turn at a time until they drop. Once they do drop turn back to the highest rpm's, and then turn 1/4 turn counter clockwise. this will be your final setting. You can then turn the rpm adjustment back down to a normal idle. Thats all there is to it
