The carburetor on a Homelite chainsaw controls the air-gas mixture that flows through the engine. Getting the precise balance between gas and air is essential to maximize your saw's performance. The saw's easy adjustable screws let you establish the perfect settings for each cutting job. These screws regulate the engine's low and high speed settings. You should adjust the carburetor whenever the chain spins when idling, dies when idling or is running sluggishly at high speed.
Before Adjusting the Carburetor Screws
Use the screwdriver to pop off the cylinder cover. Remove the air filter and give it a good cleaning with a wire brush. Replace the filter if it's old or can't be cleaned.
Use the wrench to loosen the muffler cover's bolt. Pull out the spark arrestor screen from inside the muffler and give this a cleaning with the wire brush as well.
Fill the saw with fresh gas. Use a 50:1 gas-oil ratio.
Start the saw to let it warm up. Locate the two carburetor screws. The screws are on the same side as the clutch cover, in the rear, next to the throttle handle. They are labeled "L" for low speed and "H" for high speed.
Adjusting the Carburetor
Use the small screwdriver to turn the low speed or "L" screw all the way in clockwise. Move it back out one-quarter of a turn. Remember this position.
Turn the "L" screw counterclockwise until the engine cuts out or starts making a heavy, bubbling noise. Move it back one-quarter of a turn. Remember this position.
Fine-tune the low speed screw by listening to the engine and adjusting the screw in between the two points you found in the previous steps. Listen for the cleanest sound when throttled at low speed.
Throttle the saw and use the small screwdriver to turn the high speed or "H" screw clockwise all the way or until the engine begins making a loud, high-pitched whine. Move the screw back one-quarter of a turn and remember the setting.
Throttle the saw again and turn the screw back counterclockwise until your engine begins to slow down and get sluggish. Move it back one-quarter turn and remember this setting. Fine-tune the high speed screw by adjusting it in between these two points. Listen for the cleanest, nicest sound from your engine.