First Considerations

• Before tackling any mechanical causes involving the mower engine, it is necessary to first eliminate simpler causes. Make sure that the battery on a battery-powered push mower is not dead or too low to start the mower. An electric push mower may be plugged into a bad outlet. In a gas-powered mower, the gas level may be too low. Also, old gas may have gone bad, preventing the mower from starting.
  
  

Fuel Supply Problems

• A push mower will not start if the fuel valve on the base of the fuel tank is closed. Also, a faulty spark plug will not provide the spark for the mower engine to start. Other fuel supply problems include fuel line blockage, a flooded carburetor or a faulty choke plate or fuel pump.
  
  

Solutions

• Open a closed fuel valve and if you notice the smell of unburned gas when trying to start the mower, let it rest for about 15 minutes. Try restarting the mower with the choke off. If you suspect that the gas is old and stale, siphon it out and replenish the tank with fresh gas. Inspect the spark plug, checking if it is wet or dry.