If your tiller engine isn't running smoothly, cleaning or replacing the carburetor, tuning up the engine or replacing bad gas may fix the problem.
If you left gas in the tank during the winter without adding fuel stabilizer, drain the tank and fill it with fresh gas. Add fuel stabilizer to gas to keep it fresh during the off-season.
Stale fuel can clog the carburetor, so clean and rebuild the carburetor if the tiller continues to run rough or misfire after replacing the gas in the fuel tank. Replace the carburetor if it's too clogged to clean.
Tune up the tiller engine by replacing the spark plug and oil. A dirty spark plug won't ignite the fuel properly. Old oil won't lubricate engine parts well so the engine idles roughly because the piston or pistons won't move smoothly through the cylinder.
