Injector Service; Injection Pump; Cooling System - General - Northern Lights M843NW3 Operator's Manual

SP11. INJECTOR SERVICE
1. Injectors should be checked every 1000 hours or
more often as needed. 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 combustion 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 10
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 16
from entering the cylinders.
3. Injector installation:
a. Install a new copper sealing washer in each
injector hole (
Figure 16
b. Screw in injector and tighten to 44 - 51 ft/lbs
(6 to 7 kgm) (
Figure 17
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 11
).
Figure 12
).
Figure 13
).
Figure 14
).
Figure 15
).
).
OM843NW3 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: 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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