Locate, remove and clean both the air filter and the fuel filter on the Yamaha Moto 4. Internal combustion engines require the correct flow of air and fuel in order for the engine to perform properly. If you have been using the ATV off road, the air intake could become plugged or obstructed with leaves and other debris.
Remove the spark plug wire and remove the spark plug from the engine. Clean the end of the spark plug that screws into the engine with a wire brush. If this end of the spark plug is very black with carbon, it could be an indication the fuel mixture is too rich. After cleaning the spark plug, use a gap tool to re-size the gap on the spark plug to its correct setting and replace the spark plug into the engine. Tighten the spark plug using a spark plug wrench and reconnect the spark plug wire.
Remove the filler cap for the gas tank and make sure you have gas in the tank. Locate and remove the engine oil dipstick. Inspect the dipstick to make sure the engine oil is above the "Fill" line. If the oil level is close to or below the Fill line, add oil to the engine. Observe the color of the oil. If it is very black, then it needs to be changed.
Insert the key into the ignition, turn the start switch to "Run" and press the starter button to start the engine. If you notice the engine is running rough, locate the idle screw on the carburetor and slowly turn the screw until the engine is running smoothly.
