Small Engine Carb Adjustments

Fill the fuel tank at least half full of fresh gasoline, or oil and gas mixture.

Turn the main mixture screw, on the bottom center of the carburetor, clockwise until it stops.

Turn the idle mixture screw on the side of the carburetor, clockwise until it stops.

Turn the main mixture and idle mixture screws, clockwise one and one-half turns.

Crank the engine and let it warm up, so the choke disengages. Place the throttle control on high speed.

Slowly turn the main mixture screw on the bottom of the carburetor counterclockwise, until the engine starts to sputter. This action supplies more gas to the gas and air mixture, and makes the mixture too rich for the engine to run at a steady speed.

Count the revolutions of the screwdriver, as you slowly turn the main mixture screw clockwise, until the engine starts cutting out.

Turn the main mixture screw in the opposite direction, half the number of revolutions that you counted clockwise. This achieves a mixture of air and gas, between the highest and lowest running mixtures.

Turn the engine throttle to the lowest speed, and repeat the previous two steps, to set the idle mixture screw on the side of the carburetor.

Insert a screwdriver into the idle speed adjustment screw. It is above the idle mixture screw. Turn it slowly clockwise and counterclockwise -- to achieve an even sound, while it is idling -- so it does not die, or rev the engine excessively.