DIAGNOSIS Excessive blue smoke means the engine is burning too much oil. This is caused by an over-rich fuel/oil mixture or, less commonly, worn piston rings allowing crankcase oil into the combustion chamber.
FIX Verify your fuel mixture ratio. This saw requires a 50:1 mix. Using a 40:1 or 32:1 mix will cause excessive smoke. Drain the tank and mix fresh fuel accurately. Ensure you are using a high-quality 2-stroke oil designed for air-cooled engines. An incorrect carburetor low-speed (L) screw setting too rich can also contribute.
IF THAT DIDN'T WORK The carburetor's metering lever is set too high, flooding the engine with fuel. The Zama carburetor on this model has a factory-set metering lever height. Do not adjust it unless you have the proper tool. If the mixture is correct and smoke persists, perform a compression test. A reading below 120 psi indicates worn rings or cylinder damage.
HEADS UP Never use automotive motor oil or outboard motor oil in a chainsaw. It does not burn cleanly and will cause excessive carbon buildup and smoke.