Fill the tank with gasoline and turn the fuel valve and engine to "ON" if the tiller will not start. Also, try replacing the spark plug and the air filter or emptying the gas tank and carburetor. Refill with gas.
Check the oil level to see if you need to add more. Clean the engine's air screen or remove and clean out the muffler if the engine overheats when you use the tiller.
If the tiller seems to be struggling to work correctly, inspect the depth stake to see if it is too deep. Set the stake for shallow tilling and adjust the throttle control.
Check the moisture level of the soil if it clumps into balls when you are tilling the soil. If so, wait for the soil to dry out before tilling it.