What causes the diesel generator can not start

what causes china diesel generator does not start ?   There are many reasons that diesel generator can not start. 
      First, the circuit is not working properly. Solution: Check diesel generator circuit.
       Second is the lack of battery power processing method: battery connector cable corrosion or loose connections.
       Third, poor cable connection or a charger, battery troubleshooting methods: replacement charger and battery.
      Fourth, start the motor troubleshooting methods: overhaul starter motor.
      Fifth, the control panel start circuit troubleshooting: 1. Check circuit 2 to recharge the battery terminals of the battery 3. Check cable and replace if necessary, tighten the nut 4. 5. Check the control panel to check the connection between the battery charger and the start / stop control circuit.
      Reason: 1 to 2 engine cylinder fuel oil in the fuel air fuel filter clogging 3 4 fuel system is not working properly.