Doosan D20G, Service Manual

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4TNV98 & 4TNE98 Diesel Engine Section 4. Fuel System 200
Cleaning of Nozzle
1. Clean the exterior of the nozzle, taking care not
to damage the needle.
2. Pull out the needle and clean carefully so as not
to damage it. Avoid use of hard, metallic tools.
3. Check for dents, damage, rusting and wear. Pay
special attention to the stem and seat of the
needle.
4. When setting the needle on the nozzle body after
thorough cleaning, check that it falls by its own
weight.
Installation of Fuel Injectors
1. Install a new copper gasket at the bottom of the
injector well.
2. Install the nozzle protector in the injector well.
3. Install the second copper gasket on top of the
nozzle protector.
4. Install the fuel injectors. Torque to 29.4ft·lb
(39.2N·m).
5. Install the fuel return line fitting using new copper
gaskets.
6. Tighten the fuel return line retaining nuts to
32.5ft·lb (44.1N·m).
CAUTION
When loosening or tightening the lines at the
fuel injectors, you must hold the fuel injector
with a second wrench to prevent the injector
from turning and damaging the fuel return line
fitting.
7. Reinstall the high pressure fuel lines and fuel
return line.
• Replace the high pressure fuel lines as an
assembly. Be careful not to bend any of the
high pressure fuel lines.
• Start all the high pressure fuel line nuts by hand,
leaving those nuts on the fuel injection pump
and fuel injectors untightened.
• Tighten the high pressure fuel line nuts
(Figure7-55, (2)) on the fuel injection pump.
• Tighten the high pressure fuel line nuts
(Figure7-55, (1)) on the fuel injectors.
Figure 7-55
8.
Prime the fuel system and check for leaks.