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Disassembly and Inspection of Fuel Injector of 300kw Diesel Generator

Nov. 26, 2019

After fuel injector of 300kw diesel generator has been used for a long time, if we want to check whether it is normal, can test it by spray test on test-bed. If it is found that the follows situations, we need to disassemble and inspect:

Opening pressure of fuel injection is lower than the specified value and the fuel is not atomized.

No obvious cutting or oil dripping.

Nozzle blockage.

The spray of oil mist from four spray holes is uneven, with different lengths.

Serious carbon deposit at the head of fuel injector.


How to disassemble fuel injector of 300kw diesel generator?

Firstly, loosen the pressure regulating nut and screw out the pressure regulating screw. Secondly, clamp the fuel injector upside down in the vise to loosen the fuel injector tightening cap. Then, disassemble other parts and clean it by clean diesel oil.

The carbon deposit at the nozzle head can be removed with a copper wire brush. If the needle valve is bite, clamp the end of the needle valve with the wire clamp pad interface, and pull out with slight rotation and force. The dirt on the needle valve cone shall be removed along the surface of the copper wire brush. And use a drill or steel wire with corresponding size to dredge the oil injection hole and oil path. Finally, put the fuel injection nozzle assembly in diesel oil and pull the needle valve back and forth for cleaning, until the needle valve can slide freely.


 diesel generator set

After clean injector parts of 300kw diesel generator set, if find the follow abnormal situations, we should repair or replace:

1.When the end face of the injector body combined with the needle valve body is slightly damaged, it can be grinded on the grinding plate after pulling out two locating pins. Pay attention not to touch the end face when pulling out the locating pin.

2.If face of injector pressure regulating spring is damaged, when pitting or permanent deformation occurs, we should replace.

3.Carbon deposits on the inner shoulder blades and hole wall of the tight cap of the splasher shall be completely removed.

4.If the diameter of the nozzle coupling is worn, and if serious oil leakage, it should be replaced.

5.When the spray hole has defects such as wear and increase, and affecting spray quality, we should replaced it.

6.When the wear of sealing seat surface of needle valve and needle valve body is not serious, aluminum oxide grinding paste can be used for mutual grinding and repair. During mutual lapping, do not use too much force, and the sealing surface can reach a uniform and not too wide sealing belt.

7.Because the gas in the cylinder of diesel engine flows back or small impurities enter into the nozzle, causing needle valve black or stuck, it can be reused or replaced depending on the severity after cleaning and mutual study.


The following points should be paid attention to when assembling the fuel injector of 300 kW  diesel generator set:

1.During the assembly, parts must be kept clean. In particular, the sealing parts of the fuel injector couple and the end face of the fuel injector body of the 300kW diesel generator set. Even the small debris and dust will cause the sliding block of the couple and poor sealing of the contact surface.

2.The shoulder blade surface between the tight cap of the injector and the nozzle shall be smooth and smooth without carbon deposit or burr. Otherwise, it will affect the coaxiality and perpendicularity of the installation of the fuel injection nozzle coupling parts, resulting in poor sliding performance of the fuel injection nozzle.

3.When assembly, first screw in the oil inlet pipe joint with filter element, press the copper washer tightly to ensure no oil leakage. Then place the pressure regulating spring and ejector pin into the fuel injector, screw in pressure regulating screw, until the pressure regulating spring is just contacted, then screw on the adjusting nut.

4.Clamp the fuel injector of 300 kW diesel generator set on the vise, tighten the tight cap, its tightening torque is 59 ~ 78N·m. Deformation of needle valve body will be caused by excessive torque, which affects the sliding of needle valve. If too small, it will cause oil leakage.

5.The assembled fuel injector assembly should be sealed and sprayed on the test bench. And adjust the injection opening pressure.


Starlight Power is a manufacturer of 20kw-3000kw diesel generator set, if you have purchase plan, welcome to inquire us by email sales@dieselgeneratortech.com, we will work with you.

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