Injector Service; Injection Pump - Northern Lights M844W3 Operator's Manual

SP-10. INJECTOR SERVICE
1. Injectors should be checked every 1000 hours, or
whenever necessary. Check should be made by a
Northern Lights dealer or local injection repair
station.
CAUTION: Escaping diesel fuel under pressure
can have sufficient force to penetrate the skin
causing serious personal injury. If injured by
escaping diesel fuel, see a doctor at once.
2. Injector removal:
a. Clean loose dirt from around the injectors and
the fuel lines.
b. Relieve high pressure in the fuel lines by
loosening the delivery line flare nuts at each
injector ( ).
Figure 12
c. Remove delivery lines by disconnecting from
injectors and injection pump (
all lines as an assembly; do not remove the
spacers. Cover the ends of the lines, the injector
inlets and injection pump outlets to keep dirt out.
d. Remove the return line retaining bolts (
Remove the return line (
e. Unscrew and remove the injectors (
NOTE: Do not use pry bars to remove injectors
from cylinder head.
f. After removing the injectors, discard the copper
sealing washers from the injector hole in the head
( ). Cover holes to prevent dirt and debris
Figure 17
from entering the cylinders.
3. Injector installation:
a. Install a new copper sealing washer in each
injector hole (
Figure 17
b. Screw in injector and tighten to 43 or 50 ft/lbs
(6 to 7 kgm) (
Figure 18
NOTE: Overtightening can damage injector.
c. Install return line using new copper sealing above
and below each connection. Tighten return line
retaining bolts to 22 - 30 ft/lbs.
d. Install delivery lines. Leave loose at injectors for
bleeding.
e. Pump hand level on fuel pump to fill lines.
Tighten lines at injectors. Start engine and check
for leaks using a piece of paper or cardboard.
DO NOT use hand to check for leaks.
Updated 10-11-19
Servicing
). Remove
Figure 13
).
Figure 14
).
Figure 15
).
Figure 16
).
).
OM844W3 5/21
SP-11. INJECTION PUMP
1. Since operating conditions may vary considerably, it
is difficult to give a definite interval for checking the
injection pump. But as a rule, pump settings,
maximum speed, idle speed and exhaust smoke
should be checked after every 2500 hours of
operation. Service of the fuel injection pump should
only be done if checks indicate pump malfunction.
2. Black smoke can be an indication of pump
malfunction. Before servicing the pump, check other
possible causes:
a. Check cleanliness of air filter.
b. Check valve clearances.
c. Clean and check injectors.
3. Any repair which involves disassembly of the
injection pump must be carried out by specially
trained mechanics with the proper tools and test
equipment.
NOTE: All warranties on the engine become null
and void if the injection pump seals are broken by
unauthorized persons.
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