That would be the Low speed screw, and as stated before, just turn it in all the way then bring it out 1/8 of a turn at a time, until you get the idle established. the other screw usually next to the fuel inlet(not always carb) is High speed screw,,,,,turn it out 1 3/4 to 2 turns,,,after it starts and runs,,,,do pinch test to set highspeed screw,,,,,,,,,,anyone wanna elaborate on pinch test???
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