Injector Service; Injection Pump; Cooling System - General - Northern Lights OM844W3 Operator's Manual

SP11. INJECTOR SERVICE
1. Injectors should be checked every 1000 hours.
Check should be made by a Northern Lights dealer
or local injection repair station. Have your dealer
check the fuel injection nozzle spray pattern with
injection nozzle tester. If the starting pressure is too
high or the spray pattern is off, abnormal fuel com-
bustion could take place causing low engine output
and black exhaust smoke.
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 11
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 44 - 51 ft/lbs
(6 to 7 kgm) (
Figure 18
NOTE: Overtightening can damage injector.
c. Install return line using a new sealing washer
below each connection. Tighten return line
retaining bolts to 22 - 30 ft/lbs.
d. Install delivery lines. Leave loose at injectors for
bleeding.
e. Crank engine to fill lines. Tighten lines at
injectors to 11-18 ft./lbs. Start engine and check
revised 11-8-13
Servicing
). Remove
Figure 12
).
Figure 13
).
Figure 14
).
Figure 15
).
Figure 16
).
OM844W3 11/13
for leaks using a piece of paper or cardboard.
DO NOT use hand to check for leaks.
SP12. 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.

COOLING SYSTEM - GENERAL

NOTE: Marine sets – be sure to close the sea-cock
before working on the engine cooling system.
CAUTION: The cooling water in the engine
reaches extremely high temperatures. You
must use extreme caution when working on
hot engines to avoid burns. Allow the engine
to cool before working on the cooling system.
Open the filler cap carefully, using protective
clothing when the engine is warm.
WATER QUALITY
1. Distilled, deionized, soft water is preferred for use in
cooling systems. Bottled distilled water from a food
store or water supplier is recommended. Tap water
often has a high mineral content. Tap water should
NEVER be put in a cooling system unless first tested
by a water quality laboratory. Do not use water made
by the reverse osmosis method unless it has been PH
neutralized.
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