Replace the spark plug. Replace the air filter. Empty the fuel tank. Disaassemble the carburetor and empty out any gasoline and sludge in that part. Clean the fuel line of any sludge build-up that has accumulated. Use an air blower clear out any dust and dirt that has accumulated under the engine housing.
Oh dear. This has happened to me as well. You know what if you tried trouble shooting with the manual and it still doesn't work your going to have to use your warranty and call them to replace the parts. Take it back to the store you got it from.