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Diesel Generator Flameout And Shutdown Failure

Aug. 31, 2021

During the use of diesel generators, due to improper use and maintenance, some parts have malfunctioned, resulting in a decrease in speed and automatic flameout. Before turning off the flame, according to the urgency of the speed drop and the color of the exhaust smoke, the main part and cause of the fault can be judged.


1.When the flame is turned off, the speed will gradually decrease, and the sound and color of the generator will not change abnormally. This kind of failure mostly occurs in the fuel system. According to the principle of easy first and difficult, the first thing we should check is whether there is fuel remaining in its fuel tank and whether its air holes are blocked. If there is no oil in the oil tank, it means that the supply of oil is in short supply, the pores are blocked, and negative pressure is formed in the tank, so that there is no way to maintain the supply. If there is no problem mentioned above, you should slowly check the high-pressure oil circuit from the low-pressure oil circuit to see if there is any clogging of debris and air entering. For single-cylinder engines, the high-pressure oil circuit is faulty, the fuel injection pump cannot provide high-pressure oil or the injector needle valve assembly is stuck, for multi-cylinder engines, most of the power transmission components, such as transmission gear rolling keys, spline fixing screws fall off or fracture, shaft fracture, etc.


2.The speed is unstable when the flame is turned off, and white smoke is emitted from the exhaust pipe. The cause of this failure is mostly water in the diesel. If the moisture in the oil is removed and the exhaust pipe still extinguishes with white smoke, it may be that the cylinder gasket is burned out, connected to the waterway, and enters the cylinder. If the cylinder head gasket is intact, it may be that the cylinder liner is cracked or broken, or the cylinder head is cracked, connected to the water circuit, and coolant enters the cylinder.

diesel engine

3.When the flame is turned off, the speed gradually drops, and the exhaust pipe emits thick smoke. The cause of the failure is that the diesel generator is overloaded, fuel supply is too late, and the air intake is insufficient, which causes the mixed gas to be too thick and unable to burn completely. This kind of failure is often caused by several reasons, so it is necessary to analyze and check one by one when troubleshooting.


4.When parking, the speed drops sharply and black smoke comes out from the exhaust pipe. There are two main reasons for this failure:

(1)Insufficient oil pressure in the main oil passage (insufficient oil pressure, oil return pump starting position, oil pump not supplying oil or oil deterioration, etc.). Poor lubrication of the crankshaft and bearing bush surface causes the burning bush to hold the shaft , the diesel generator is forced to stall.

(2)When replacing the piston and cylinder liner, the clearance between the two is too small. After the diesel generator is put into operation, the piston is heated and expanded, causing the diesel generator to stall.


5.When the flame is turned off, the power of the generator suddenly drops, and the speed drops sharply, accompanied by abnormal noise. The main reasons for this failure are broken crankshaft or piston pin, broken connecting rod bolt or loose nut, broken valve spring or broken end of valve stem. Check carefully to find out the specific cause of the failure and eliminate it. The diesel generator can be restarted until the cause of the fault is found and eliminated.


Jiangsu Starlight Electricity Equipments Co.,Ltd., as an OEM supporting manufacturer authorized by Cummins to provide Chinese diesel generator sets, has professional manufacturing technology, perfect quality management system and strong R&D technical strength. It can provide users with generator sets of various specifications from 15KW to 2500KW. It can also provide users with one-stop service of design, supply, debugging and maintenance at any time. welcome contact us by email sales@dieselgeneratortech.com

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