During the operation of the diesel generator set, the accelerator pedal is in the oil supply position, but the speed is gradually reduced or suddenly decreased until it is self-extinguishing. According to the self-extinguishing, the speed of the speed reduction and the color of the exhaust gas are respectively introduced as follows:

　　1. When the flame is turned off by itself, the speed is gradually reduced, but the sound of the diesel generator set and the color of the exhaust gas are not abnormal. These characteristics are mostly caused by fuel system faults. For example, the fuel tank has no oil, the oil passage enters the air, the oil circuit is blocked, etc.

　　2. When the flame is self-extinguishing, the speed is gradually reduced, but the exhaust pipe is black smoke or even smoke. This kind of situation is mostly caused by air filter or intake pipe blockage.

　　3. When the flame is turned off by itself, the speed is suddenly reduced, and the black smoke is generated. The causes of the faults are as follows:

　　1. The clearance between the piston and the cylinder is too small. When the temperature of the diesel generator set rises, the piston is stuck by the cylinder.

　　2. The lubricating oil is insufficient, too thin, the temperature rises, and the diesel oil is infiltrated, so that the new moving parts of the relative moving parts are poorly lubricated, resulting in burning the tiles and holding the shaft.

　　3, stop running by itself, the speed is suddenly reduced, accompanied by abnormal noise, the common cause of this fault is the crankshaft or piston pin broken