1. The startup program is incorrect: verify whether the startup program is correct.
2. The starting speed of the engine is too low: check the starting speed of the engine by hand.
3. Start assist device is required in cold weather: Check whether the cold start assist device is working normally.
4. Air in the fuel system: Exhaust the fuel system and check for leaks.
5. Insufficient oil supply: Check whether the oil return line is connected to the bottom of the oil tank.
6. Fuel drain backup: Make sure the oil return line is connected to the bottom of the fuel tank.
7. Fuel pump relief valve failure: check the relief valve. Replace if necessary.
8. Oil pump failure: check the oil pump. Replace if necessary.
9. Large air intake resistance: Check whether there is resistance in the air intake system.
10. Fuel contamination: Verify by running the engine with clean fuel in a temporary tank.
11. Wrong adjustment of valve or fuel injector: Adjust the valve and fuel injector.
12. Fuel injector failure: check the fuel injector. Replace if necessary.
13. The oil level in the fuel tank is low: fill up the fuel tank.
14. Electric or manual fuel shut-off binding: Check for loose wires and verify that the solenoid valve is working. Check that the manual shutoff level is not binding on the injection pump.
15. Oil pump failure: check the oil pump. Replace if necessary.
16. Fuel drain backup: Make sure the return line is connected to the bottom of the fuel tank.
17. Fuel injection pump failure: perform a fuel injection pump test.
18. The timing of the fuel injector pump is incorrect: adjust the timing of the fuel injector.
