Doosan 9/270 Operation And Maintenance Manual page 57

54 PERIODICAL INSPECTION AND MAINTENANCE
FUEL SYSTEM
The fuel injection pump and injector nozzles are precisely
manufactured, and therefore, using fuel which contains water or dust
particles will result in either injection pump plunger seizure or injector
nozzle seizure. A fuel filter element blocked with sludge or dust
particles will lead to reduced engine output.
Perform inspection and maintenance periodically as follows:
Fig. 15
A Filter element
B Drain valve
Draining Water from Fuel Filter/separator.
The fuel filter/separator is provided to allow water to be drained from
the fuel system. Water is heavier than fuel so any water contained in
the system will collect in the bottom of the bowl.
Place a suitable container under the separator to prevent any spillage
inside the machine.
Slacken the drain valve 'B' until water drains from the vent tube.
When all the water has been evacuated, tighten the drain valve 'B'.
Fuel filter/separator element change.
NOTE: The cartridge and bowl contain fuel. Take care not to spill it
during disassembly and reassembly.
The fuel filter/separator also provides primary filtration and the element
'A' should be changed every 500 operating hours or 6 months,
whichever comes first.
Change procedure:
Disconnect fuel sensor (where fitted). Loosen drain plug B and empty
fuel into suitable container
Fig. 16
Unscrew the element 'A' from the head taking care not to spill fuel
inside the machine. Remove fuel sensor (where fitted) and re-fit to new
filter element.
9/270, 9/300, 12/235, 17/235, 21/215, 9/270HA, 9/300HA, 10/300HA, 12/235HA, 17/235HA, 21/215HA
Discard the old element into a suitable container.
Using a clean cloth, wipe the sealing face of the filter/separator head
to ensure correct seating of the sealing ring.
Fill the element/bowl assembly with clean fuel oil then apply a light coat
of clean engine oil to the new element seal ring.
Screw the new element onto the head firmly by hand.
The engine has a self priming system that purges air from the fuel
system.
AIR INTAKE SYSTEM
Air cleaner
Engine performance and life vary with the air intake conditions.
A dirty air cleaner element reduces the amount of intake air, causing
reduced engine output and possible engine damage.
Also, a damaged element leads to abrasion of cylinders and valves,
resulting in increased oil consumption, reduced output and shortened
engine life.
The filter element should be changed at 500 hours or 6 months,
whichever comes first, or sooner if the restriction indicator shows red.
See below.
Fig. 17
A Normal
B Clogged
C Indicator
D Red signal
Air cleaner with dust indicator
This indicator is attached to the air cleaner. When the air cleaner
element is clogged, air intake resistance becomes greater and the dust
indicator signal turns to red indicating the element needs to be
changed.
When the signal turns to red, replace the element. Then press the dust
indicator button to reset the indication.