Lovol 1004-4, User Handbook Manual, Page: 61 / 87

Air-Discharge of the Fuel System and other Relevant Information
Fuel
Low quality fuel will impair the fuel pump and affect the engine performance, so only the fuel recommended by
the engine manufacturer should be used.
Only the clean fuel with right viscosity grade should be used.
The plunger piston, fuel outlet valve and injectors should be lubricated with fuel of right viscosity grade.
If the fuel viscosity grade is too low, the components might be choked.
If the fuel viscosity grade is too high, the combustion will be influenced.
Due to the extremely small clearance between moving parts, particulates such as dust and iron rust will cause
serious abrasion of the fuel injection system.
In order to keep the fuel clean, the fuel filter should be maintained or replaced regularly. And the fuel tank
should be maintained regularly.
High concentration of sulfur in the fuel will do harm to the fuel pump. The sulfur dioxide formed through
burning, will combine with water and turn into sulfuric acid, which in turn will corrode the fuel pump and
relevant components. So only the fuel with low concentration of sulfur should be used.
The water in the fuel will cause the inner part of the fuel pump to corrode, as a result the moving parts might be
choked.
So make sure there is no water in the fuel.
If there is carbon residual on the injector, the engine performance will be affected. So the fuel which can leave
less carbon residual after burning should be used.
Fuel filter
Considering the negative effect of the foreign substance in the fuel, the fuel should be suitably filtered.
Obey the instructions about fuel filter.
Eliminate air from the fuel system and start fueling
After installation of the fuel pump, the air in the fuel system from the fuel tank to injectors should be eliminated
during the initial running. The air in the fuel will decrease the power output and startability, and cause unstable idle
speed.
The fuel lift pump on the fuel supply pump is used to eliminate air from the fuel system during the initial
runnings.
1. Completely loosen the nut on the fuel lift pump.
2. Open the overflow valve or loosen the air-bleed screw on the fuel filter.
3. keep running the fuel lift pump, until there are no bubbles in the fuel flowing out of the overflow valve or
air-bleed screw air-bleed screw
。
4. close the overflow valve or fasten the air-bleed screw
。
5. Open the overflow valve on the fuel pump and continue to run the fuel lift pump, until there is no bubbles in the
fuel flowing out of the overflow valve.
6. Run the start motor until the engine is started.
Thus the air elimination and start fueling is completed.
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