Look for the carburetor fuel adjusting bolts, which may vary by model. There is a prime or high speed fuel trim, a low or idle speed fuel trim, and an idle stop screw or throttle. If the carb is severely out of adjustment, set the high and low speed settings to their default values by turning them clockwise until they stop and then opening them 1-1 / 4 turns for the high speed screw and one turn. for low speed. screw.