If your Husqvarna chainsaw is showing signs of smoking, stalling, or erratic performance, you may be able to improve its operation by adjusting the carburetor. While the carburetor comes factory adjusted when the saw is new, it’s common for the adjustment to slip over time, so knowing how to restore it can be a useful skill for maintaining not just your Husqvarna chainsaw but other gas-powered chainsaws as well.
The carburetor in a Husqvarna chainsaw mixes air and fuel in the proper ratio and supplies the mixture to the engine. The carburetor regulates the amount of fuel that flows into the engine, depending on the position of the throttle trigger. The carburetor has adjustment screws that control the amount of fuel in the mixture, which can be adjusted to ensure the engine runs smoothly and efficiently.
When you adjust the carburetor, you are regulating the ratio of fuel and air in the carburetor. If the mixture is too rich, meaning there’s too much fuel, the combustion is incomplete, and the chainsaw will produce smoke. If the mixture is too lean and there isn’t enough fuel, the saw will race, potentially damaging the engine and causing it to be underpowered. If the mixture is extremely rich or lean, the saw won’t run at all.
First, set your chainsaw on a flat and stable surface. Turn on the chainsaw and let it run for approximately five minutes to warm up
The adjustment screws are located on the motor housing near the pull rope, usually arranged in a triangle with two next to each other and a third above them. You should ideally use a carburetor adjustment tool to turn the screws rather than a flat-head screwdriver, as this will make the job easier. Ensure that the tool is designed for use with Husqvarna engines, as other brands may not be compatible.
The screws are labeled (L), (H), and (I), also called (T). L stands for low speed, which regulates the fuel mixture when the chain is turning slowly; H stands for high speed, which regulates the mixture when the saw is running at full speed; and T regulates the mixture when the chainsaw is idling. To properly adjust the carburetor, you must adjust all three screws accordingly.
Begin by adjusting the L screw first, followed by the T screw, and finish with the H screw. Ensure that the saw is on a flat surface and that you have easy access to the screws. Do not set the chain brake, as the chain must spin for proper adjustment. Start the chainsaw and adjust the L screw by turning it clockwise until the engine almost stops. Then, turn it counterclockwise until the engine runs smoothly, and test the adjustment by squeezing the throttle trigger and noting smooth acceleration. This step may require some fine-tuning to achieve the desired outcome. Next, adjust the I or T screw by turning it clockwise until the chain begins to move, then turn it counterclockwise until the chain stops moving.
The most crucial step is adjusting the H screw. Turn it counterclockwise as far as possible without forcing it. The engine will sound rough, but gradually turn the screw clockwise until the engine sounds smooth and accelerates effortlessly when you squeeze the trigger.
If the carburetor goes entirely out of adjustment and the engine won’t even start unless you hold down the throttle, you can reset it with a straightforward procedure. Turn both the H and L screws clockwise as far as possible without forcing them, then rotate each screw clockwise 1 1/2 turns. This should allow the engine to run without the throttle, and from there, you can fine-tune the adjustment.
Gently press the throttle trigger. The exhaust should not emit smoke, and the engine should accelerate smoothly.
Husqvarna Chainsaw Carburetor FAQ
Why does my Husqvarna chainsaw need its carburetor adjusted?
Over time, the factory adjustment on the carburetor can slip and cause issues such as smoking, stalling, or erratic performance. Adjusting the carburetor can restore the proper fuel-air mixture and improve the chainsaw’s performance.
What are the three adjustment screws on a Husqvarna chainsaw carburetor?
The screws are marked (L), (H), and (I) or (T). L stands for low speed, H stands for high speed, and T regulates the mixture when the chainsaw is idling.
What’s the correct order to adjust the carburetor screws?
Start with the L screw, then move on to the T screw, and finish with the H screw.