My Small Front-Tine Troy-Bilt Tiller Has No Power

Spark Plug

• Whether the engine is two-stroke or four-stroke, it will have a single spark plug that ignites the air-fuel mixture inside the cylinder. A dirty, damaged or incorrectly gapped spark plug can significantly reduce engine power. Remove the spark plug with a 5/8-inch spark plug wrench and inspect it for fouling, worn electrodes and cracking or chipping. Clean a fouled plug; replace a damaged or worn one. Check the gap with a gauge and carefully bend the electrode to correct it if necessary.

Air Filter

• The tiller's air filter allows oxygen to enter the engine while removing particulate matter that would quickly damage the interior of the machine. Because tillers operate in dusty and dirty conditions, it's important to check the air filter regularly. A clogged filter reduces the amount of air available to the engine, which in turn reduces engine power. Clean a dirty air filter with soap and water. For some models, the manufacturer recommends dipping the clean filter element in engine oil.

Fuel Quality

• The final element necessary for good performance is fuel. A tiller with a four-stroke engine uses gasoline, while a tiller with a two-stroke engine requires a mixture of gasoline and two-cycle oil at the ratio stated in the owner's manual. Both fuels have a limited lifespan, so drain the fuel system whenever you plan to store the tiller for more than a few weeks. Stale fuel clogs the fuel system and robs the engine of power.

Carburetor

• The carburetor is a delicate device that combines air and fuel before sending it to the tiller's engine for combustion. If the carburetor is out of adjustment, or becomes clogged with dirt or deposits from stale fuel, it can cause a range of problems including hard starting, low power, rough running and stalling. Carburetor repair and adjustment require some mechanical knowledge, so you may need to have a professional service the tiller.