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How to Adjust the Idle on a Craftsman Chain Saw

A Craftsman chain saw comes with an adjustable idle speed. By regulating the flow of gas in the carburetor, you can adjust the idling speed of your saw. This screw will open and close a jet inside the fuel mixing chamber on the carburetor. Over-adjusting the carburetor can damage the carburetor and piston. It will also cause the chain to spin during idling, which can be dangerous for the operator.

Open the gas tank and fill the Craftsman with freshly mixed chain saw fuel. Adjusting when the tank is empty can damage the carburetor. Unscrew the top air filter cover with the screwdriver.

Pull the air filter from the box. Wash the filter in warm, soapy water. Rinse with cool water. Let it dry for several hours before reusing it. Do not adjust the carburetor with a dirty air filter.

Start the Craftsman’s engine and let the chain saw idle for a few minutes to warm the engine. Locate the three letters on the starter side of the chainsaw, which read “H,” “L” and “T.” Insert the small screwdriver into the hole marked “T” for the idle speed.

Rotate the “T” screw clockwise to increase the speed of the idle. Rotate the screw clockwise until the chain begins moving on its own. Turn the screw counterclockwise slowly using 1/8-increments until the chain stops spinning. Locate the highest idle speed before the chain starts spinning on its own. This will be your optimum idle speed.

Craftsman 3.3 Chainsaw Won't Idle

The two remedies most likely to cure an engine that doesn't idle properly are to clean the air filter and adjust carburetor's idle screw, and cleaning the air filter comes first because the idle adjustment will be incorrect if it's dirty. The filter is installed behind a cover in the housing just above the handle. The Craftsman 3.3 chain saw carburetor is equipped with three adjustment screws, and although Sears recommends that you have these serviced by an authorized professional, you can safely adjust the idle and low-speed screws yourself. After cleaning the air filter and the spark arrestor screen, which is behind the muffler, you're ready to adjust the carburetor. Turn the idle screw clockwise until the chain starts turning, then back it off to the point at which the chain stops. The Craftsman 3.3 chainsaw is an older model, and yours is likely to have seen many service hours. This is a potentially dangerous condition and can be corrected by servicing the clutch.


Adjusting the idle screw may warrant adjustment of the low-speed and high-speed screws as well.

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