Fuel system maintenance for soundproof diesel generator

by Generator D. Diesel Generator

Today Starlight silent diesel generators manufacturer shares fuel maintenance and fuel injector faults with you. Hope this article is helpful to you.


Fuel System

The fuel system of the standard soundproof diesel generator includes: fuel tank, fuel supply pump, fuel filter, manual oil pump, fuel injection pump, fuel injection nozzle and related oil pipeline.


Only fuels that meet the quality specified in the following standards shall be used. It must be kept clean during refueling and fuel system operation. When working on the fuel system, it must be confirmed that the engine has cooled down. The splash of fuel on hot surface or electrical components may cause a fire.


Fuel specification

The composition of the diesel oil has a very important effect on the operation and service life and the emission components of the diesel engine. In order to obtain the specified power, fuel economy and the emission standards specified by the local environmental protection department, only clean light fuel that meets international and national standards should be used.


Light diesel oil is used for fuel in high-speed diesel engines above 1000r/min. The current standard for light diesel oil products is GB252-2000 "light diesel oil" standard. The grade of diesel oil is based on the freezing point of diesel. Customers should choose the appropriate diesel grade according to the temperature of the workplace. 

 soundproof generator set


a. The fuel recommended in the operating manual must be used. For diesel engines, the use of low-quality fuel can cause the control rod to stick and the engine to rotate at an excessive speed, resulting in damage to the generating set or even serious personal injury. Inferior fuel will also shorten the maintenance cycle, increase maintenance costs, and reduce the normal service life of the gen set.

b. When adding fuel, there is usually a risk of fire and explosion. No smoking when refueling.

c. Do not allow the fuel oil to overflow the fuel tank. The fuel tank cover should be sealed safely.

d. Water in the fuel can cause corrosion of metal parts in the fuel system, and it can easily cause fungi and microorganisms to grow in the tank, which can block the filter. When the fuel water content is relatively large, it is recommended that the user install a oil-water separator for the genset. Make sure that the fuel entering the body is free of water or other impurities. All models of medium and high units can be equipped with oil-water separators according to the requirements of users. The oil-water separators are not part of the standard configuration when the unit leaves the factory. When users need to order, it should be separately stated.


Replace fuel filter

a. Keep it clean and do not allow any dirt to enter the fuel system.

b. In order to avoid fuel splashing on hot surface and causing fire, the fuel filter replacement must be carried out under the condition of cooling machine.

c. Remove the filter and apply a little oil to the gasket of the new filter. Screw the filter by hand to bring the gasket into contact with the seat. Then tighten again, do not screw more, and exhaust the air from the fuel system.

d. Start the unit and check for leaks.


Fuel injection pump

a. The fuel injection pump is driven by a timing gear transmission mechanism in the diesel engine. The pump setting is measured with a lift meter when the base circle of a particular crankshaft angle rises.

b. The fuel injection pumps used in medium and high diesel generator sets are superior in quality and reliable in performance, which can ensure the long-term normal use of users.


Fuel spray nozzle

a. Equal distribution of fuel oil for reliable ignition and combustion.

b. Inject fuel oil directly into the combustion chamber and provide optimal mixture of fuel oil and air. The injection pressure can be pre-adjusted by a spring.


What are fuel injector faults?

1.A little or no fuel injected.


(1) There is air in the fuel supply system.

(2) Seizure of the fuel injector nozzle.

(3) Abnormal fuel supply from the fuel injection pump.

(4) Oil leak at high-pressure fuel pipes.

(5) Wear of fuel injector nozzles.


Prime the fuel system.

Let a professional serviceman check and replace the nozzle assembly.

Refer to fuel injection pump fault for troubleshooting.

Tighten the pipe locknut and replace the pipes with crack, make replacement if required.

Let a professional serviceman replace the nozzle assembly.


2.Too low fuel injection pressure.


(1) Lose pressure regulating screw.

(2) Deformation or break of the pressure regulating spring.

(3) Seizure of needle valves.


Let a professional serviceman readjust the screw to the defined pressure and tighten the locknut.

Let a professional serviceman replace the injector spring.

Let a professional serviceman replace the nozzle assembly.

3.Too high fuel injection pressure.


(1) Pressure regulating spring force too high.

(2) Seizure of needle valves.

(3) Block of the injection holes.


Let a professional serviceman readjust the spring force.

Let a professional serviceman replace the nozzle assembly.

Let a professional serviceman check and clean the injection holes. Replace the injector if necessary.


4.Fuel leak at fuel injector.


(1) Break of pressure regulating springs.

(2) Damage of needle valve facing.

(3) Seizure of needle valves.

(4) Deformation of tightening cap.

(5) Poor contact between nozzle and injector body.


Let a professional serviceman replace springs.

Let a professional serviceman replace the nozzle assembly.

Let a professional serviceman replace the nozzle assembly.

Let a professional serviceman replace the caps.

Let a professional serviceman repair or replace the nozzle assembly. Replace the injector if required.

7.The surface of needle valve is burn or in blue-black.


The engine is overheating.


Check the cooling system and do not over-load the engine for a long time. Let a professional serviceman check the nozzle assembly and make replacement if necessary.

Starlight Power provides 20kw to 2500kw diesel generator set with various brand, including Cummins, Perkins, Volvo, Deutz, Ricardo, Yuchai, SDEC, Weichai, etc. Contact us: or call us by mobile phone +8613481024441 ( same as WeChat number ).

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About Generator D. Senior   Diesel Generator

111 connections, 2 recommendations, 677 honor points.
Joined APSense since, September 11th, 2017, From Jiangsu, China.

Created on Mar 22nd 2021 01:50. Viewed 179 times.


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