If your leaf blower runs rough, first make sure there's fresh gas in the tank—old gas accumulates water and burns poorly. Replace the gas in the tank if it’s older than 3 months. Add fuel stabilizer to the tank to help keep the fuel fresh.
Perform preventive maintenance on the leaf blower. Preventive maintenance includes cleaning or replacing the air filter and spark plug. A dirty air filter will starve the engine of air so it will run rough. Oil and carbon deposits on the spark plug electrode can interfere with fuel ignition inside the cylinder—causing the engine to run rough. Cleaning the air filter and replacing the spark plug will help the engine run smoothly.
Cracks in fuel lines will cause the engine to sputter and run rough because the damaged fuel lines won’t be able to supply enough fuel to the carburetor. Check the fuel lines and replace them if you find cracks in the lines.
Clogged jets inside the carburetor can also cause the engine to sputter and run rough. If the engine still runs rough after doing preventive maintenance and the fuel lines are okay, then you may need to rebuild or replace the carburetor.