Blue smoke coming from a lawn mower usually indicates an issue with the engine, specifically with the combustion process. This is often caused by oil being burned in the engine, and it can result from a few different problems. Here are some steps to troubleshoot and fix the issue:
Check the oil level: Ensure that the oil level in the lawn mower is at the correct level. Too much oil can cause excessive oil consumption and lead to blue smoke. If the oil level is too high, drain some oil until it reaches the proper level.
Check for oil leaks: Inspect the lawn mower for any signs of oil leaks. Leaking oil can find its way into the combustion chamber and cause blue smoke. Look for oil puddles or drips under the mower and check for oil around the engine and the crankcase.
Check the air filter: A dirty or clogged air filter can disrupt the air-fuel mixture, leading to incomplete combustion and increased oil consumption. Remove the air filter and clean or replace it if necessary.
Inspect the spark plug: A fouled spark plug can also cause improper combustion. Remove the spark plug and check its condition. If it's dirty or worn out, clean it or replace it with a new one as recommended by the manufacturer.
Check the PCV valve: The Positive Crankcase Ventilation (PCV) valve is responsible for recycling gases from the crankcase back into the engine. If it's clogged or malfunctioning, it can lead to oil consumption and blue smoke. Clean or replace the PCV valve as needed.
Inspect the piston rings: Worn or damaged piston rings can allow oil to enter the combustion chamber and cause blue smoke. Checking and replacing the piston rings is a more involved task and may require professional assistance if you're not experienced with engine repairs.
Verify the carburetor and fuel system: A malfunctioning carburetor can cause an incorrect air-fuel mixture, leading to combustion issues. Check the carburetor and fuel system for any problems and clean or repair them as necessary.
If you're comfortable working with small engines and have some experience with lawn mower repairs, you can try addressing these issues on your own. However, if you're unsure or the problem persists after attempting these fixes, it's best to take the lawn mower to a qualified mechanic or a lawn equipment repair shop for a more thorough inspection and repair. Always prioritize safety when working with machinery and engines.