What are the reasons for the unsuccessful start-up of diesel generators

What are the reasons for the unsuccessful start-up of Cummins diesel generator sets
1) Any fuel or insufficient amount of fuel;
2) The temperature of the engine cylinder cooling water is low;
3) Low battery voltage;
4) Air jet pump;
5) Start motor malfunction;
6) Control circuit malfunction.
handle:
1) Based on the above checks, heat or fuel is necessary.
2) Check for clogged fuel filters.
3) Check the fuel injection pump and the air release plug of the exhaust gas.
4) If the battery voltage is too low, it should be balanced charging. Check and handle the faulty starter motor accordingly.
5) Check and troubleshoot the control circuit.