Northern Lights Lugger ONL753W2 User manual

ONL753W2
For Models: NL753W and NL753W2
OPERATOR’SMANUAL
Marine Generators | Marine Diesel Engines | Land-Based Generators

Diesel engine exhaust and some of its constitu-
ents are known to the State of California to cause
cancer, birth defects, and other reproductive harm.
— CALIFORNIA —
Proposition 65 Warning:
Northern Lights
4420 14th Avenue N.W.
Seattle, WA 98107
Tel: [phone]
Fax: [phone]
Copyright ©2009 Northern Lights, Inc.
All rights reserved. Northern Lights™, and
the Northern Lights logo are trademarks of
Northern Lights, Inc.
Printed in U.S.A.
PART NO.: ONL753W2 10/09

ONL753W2 10/09
3
Read this operator's manual thoroughly before starting to operate your equipment.
This manual contains information you will need to run and service your new unit.
OPERATOR'S MANUAL
for Models
NL753W & NL753W₂
INTRODUCTION ....................................................4
Models Included .................................................4
Model Numbers..................................................4
Serial Numbers ...................................................4
WARRANTY ............................................................5
SAFETY RULES.....................................................5
COMPONENT LOCATIONS
Industrial Generator............................................6
CONTROL PANEL
S-1B Control Panel.............................................7
OPERATING PROCEDURES
Break-in Period...................................................8
Before Starting....................................................8
Starting................................................................8
Operating ............................................................8
Stopping..............................................................8
Shutdowns and Alarms.......................................9
Spare Parts..........................................................9
SERVICING SCHEDULE CHART.................... 10
SERVICING
Lubrication - General....................................... 12
Checking Oil.................................................... 12
Oil Changes ..................................................... 12
Changing Oil Filter.......................................... 12
Air Filter .......................................................... 13
V-Belts ............................................................. 13
Valve Clearances.............................................. 13
Fuels - General................................................. 14
Fuel Filters....................................................... 14
Bleeding the Fuel System................................ 15
Injector Service........................................ 16 - 17
Injection Pump................................................. 17
Cooling System - General................................ 17
Cooling System Flushing................................. 18
Clean Radiator ................................................. 18
Generator End.................................................. 18
Electrical System - General............................. 18
Glow Plugs....................................................... 19
Booster Batteries.............................................. 19
Battery Care..................................................... 19
Winterizing / Out-of-Service ........................... 19
TROUBLESHOOTING
Electrical.......................................................... 20
Engine...................................................... 21 - 23
WIRING DIAGRAMS
DC Electrical ................................................... 24
AC Electrical ................................................... 25
Proprietary Information
This publication is the property of Northern Lights, Inc.
It may not be reproduced in whole or in part without the written permission of Northern Lights, Inc.
© Northern Lights, Inc. All rights reserved. Litho U.S.A. Publication number ONL753W2 10/09
Table of Contents

ONL753W2 10/09
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Servicing of generator sets presents unique problems.
In many cases boats cannot be moved to a repair
facility. Generator sets cannot be compared to the
servicing of automobiles, trucks or even farm equip-
ment. Failures often occur in remote areas far from
competent assistance. Generator sets are taxed far
more severely than auto or truck engines; therefore,
maintenance schedules must be adhered to more
strictly.
Failures begin with minor problems that are
overlooked and become amplified when not
corrected during routine maintenance.
As operator, it is your obligation to learn about your
equipment and its proper maintenance. This is not a
comprehensive technical service manual. Nor will it
make the reader into an expert mechanic. Its aim is
to aid you in maintaining your unit properly.
Introduction
W
NL - Northern Lights industrial generator set Model number of engine block
Bore Cylinders
75 mm 3
Serial Numbers
MODELS INCLUDED
This manual covers the operating instructions for:
NL753W and NL753W2 industrial generator sets.
Model Numbers
Model numbers give the unit's application, block model, aspiration, and RPM:
Designates new
winding within
generator set
++
Unit Identification
Northern Lights industrial generator set with a
753 engine, PXK2 series generator end, and AVR.
NL 753
NL753W =
Your set has three serial numbers: 1an engine number stamped
on the block, 2a generator plate, and 3a generator set plate.
Use the serial number on the generator set plate when ordering parts
or in correspondence. The generator set plate is found on the service
side of the generator and resembles the drawing in Figure 1.
Figure 1: Generator set serial number plate.
Northern Lights industrial generator set with a 753
engine, PXK2 series generator end, AVR, Tier II.
NL753W2 =

ONL753W2 10/09
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CAUTION: This symbol is used throughout
this book to alert you to possible danger areas.
Please take special notice of these sections.
A warranty registration certificate is supplied
with your set. It entitles the original purchaser of
our equipment to a warranty covering material
or assembly faults. The extent of coverage is
described in the Limited Warranty Statement. We
recommend that you study the statement carefully.
NOTE: If the warranty is to apply, the servicing
instructions outlined in this manual must be
followed. If further information is needed, please
contact an authorized dealer or the factory.
CAUTION: Accident reports show that careless use of engines causes a high percentage of accidents.
You can avoid accidents by observing these safety rules. Study these rules carefully and enforce them on the job.
• Use caution in handling fuel. Never re-fuel a hot
or running engine. Do not smoke while filling
fuel tank or servicing fuel system.
• Keep your hands, feet, hair and clothing away
from power-driven parts.
• Check for any loose electrical connections or
faulty wiring.
• Engines should be operated only by
knowledgeable, qualified personnel.
• Look completely around engine to make sure
that everything is clear before starting.
• Do not operate an engine that isn't in proper
working order. If an unsafe operating condition is
noted, tag the set and control panel so others will
also know about the problem.
• Provide first aid kits.
• Never leave engine without proper security.
• Turn the coolant tank cap slowly to relieve
pressure before removing. Add coolant only
when the engine is stopped and cool.
• Mount a fire extinguisher near engine.
• Always disconnect the battery ground strap
before making adjustments.
• Operate engines in properly ventilated areas.
• Keep trash and other objects away from engine.
• Escaping fluids under pressure can penetrate
your skin. Use a piece of cardboard or wood,
not your hands, to search for leaks.
• Avoid wearing loose clothing without a belt
when working around engines.
• Do not oil or grease engine while it is running.
Safety Rules
Warranty

ONL753W2 10/09
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Industrial Generator Component Locations
15. Exhaust Outlet
16. DC Circuit Breaker
17. Starter
1. Junction Box
2. Air Filter
3. Crankcase Vent
4. Lube Oil Fill
5. Coolant Fill
6. Injection Pump
7. Dipstick
Figures 2-A and B: NL753W
8. Fuel Inlet & Return
9. Block Water Drain
10. Oil Filter
11. Fuel Lift Pump
12. Secondary Fuel Filter
13. Hourmeter
14. Control Panel
18. Alternator
19. Radiator Shroud

ONL753W2 10/09
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Control Panel
Figure 3: Series 1-B Generator Control Panel
1. SHUTDOWN BYPASS-PREHEAT SWITCH
There are two functions built into this switch:
preheating the engine and bypassing the engine safety
shutdown circuit, enabling a quicker start. Hold the
switch in the ON position for approximately 10 to 20
seconds before starting a cold engine. Holding the
switch ON for too long can burn out the glow plugs.
NOTE: Three position Engine Control switches must be
in the RUN position during preheating. Preheat switch
must be held in ON position during starting.
2. ENGINE CONTROL SWITCH
To start the engine, hold this switch in the START
position until the engine is running.
NOTE: Excessive cranking of marine sets equipped
with water lift muffler systems can cause engine
damage. See page 8.
After the engine starts, release the switch and it will
return to RUN position. To stop the engine, hold the
switch in the STOP position.
NOTE: The rocker switch is used on Series 1 panels
only, and has a light that glows when the set is running.
3. HOUR METER
Keeps track of engine running time.

ONL753W2 10/09
8
BREAK-IN PERIOD
1. The first 100 hours on a new or reconditioned
engine are critical to its life and performance.
2. Constantly check the engine temperature and oil
pressure.
3. Oil consumption is greater during break-in as
piston rings take time to seat.
4. Break-In Oil Changes: Change engine oil and
filter at 50 hours. Change oil and filter again at
250 hours (consult Lubricants section for oil
recommendation).
Operating Instructions:
Maintain at least a 75% load on your generator
set for the first 100 hours. If this is not possible,
maintain no less than a 50% load to ensure proper
seating of the piston rings. Vary the load to help
seat the rings.
BEFORE STARTING
1. Check the coolant level by removing the pressure
cap from the expansion tank or radiator. In order to
give the cooling water an opportunity to expand, the
level should be about 1 in. (2.5 cm) below the filler
cap sealing surface when the engine is cold.
CAUTION: Use protective clothing and open the
filler cap carefully when the engine is warm to
prevent burns.
2. Check the oil level in the crankcase with the dip-
stick. The oil level must be in the waffled area on the
stick. Never allow the level to go below this area.
Always add the same viscosity of oil as is already in
the crankcase.
3. Check the fuel tank level and open any fuel valves.
NOTE: The battery switch must always be kept
ON while the engine is running. If the switch is
turned OFF while the engine is running, the
battery charging regulator could be ruined.
STARTING
1. Hold the Shutdown Bypass-Preheat switch in the ON
position for 10 to 20 seconds before starting a cold
engine. Holding the switch too long can burn out the
glow plugs. This step is not necessary if the engine is
already warm.
2. While holding the Shutdown Bypass-Preheat switch
in the ON position, push the Engine Control switch
to the START position.
3. As soon as the engine starts, release both switches. Do
not crank the starter for more than 20 seconds
consecutively. If the engine fails to start with the first
attempt, be sure that it has stopped completely before
re-engaging.
OPERATING
1. Check oil pressure often. Oil pressure must be
above 15 PSI. The water temperature must be
below 225°F (107°C). Check the AC voltage and
frequency. If these deviate from normal levels, shut
down the generator set and investigate.
1. Let the unit run unloaded for a three to five minute
warm-up period.
2. Add electrical load.
STOPPING
1. Remove electrical load from the generator set.
2. Move the Engine Control switch to the STOP
position momentarily.
Operating Procedures

ONL753W2 10/09
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SHUTDOWNS AND ALARMS
1. Generator sets have shutdown systems to stop the
engine in the event of high water temperature or low
oil pressure.
Other alarms and shutdowns are available as
optional equipment.
NOTE: Do not rely on your shutdown to the
exclusion of careful gauge monitoring. Watching
your gauges can prevent damage to the unit and
dangerous power losses.
2. Do the following when your warning or shutdown
system is activated:
a. Check the temperature gauge.
Industrial sets: If above 230°F (110°C), shut
off the engine immediately.
b. Use the Trouble Shooting Guide on page 19 to
isolate the cause of the overheat.
CAUTION: Do not remove the water fill
cap of an overheated engine. Escaping high
temperature steam can cause severe burns. Allow
the engine to cool and then remove the cap slowly
using protective clothing.
c. Make repairs.
Restart your Industrial set after the temperature
gauge registers below 225°F (107°C).
d. Watch the temperature gauge regularly and
turn off the unit if the temperature rises above
230°F (110°C) on Industrial sets. Repeat trouble
shooting.
3. If shutdown is activated and the temperature gauge
shows temperature within normal temperature range:
a. Check the engine crankcase oil level.
b. If the oil level is low, fill with recommended
lubricating oil and restart. Watch the oil pressure
gauge carefully and shut off the engine if it does
not show a normal reading (20-60 PSI) after a
few seconds of operation.
c. If the oil level is normal, DO NOT restart the
engine. Call your dealer for assistance.
SPARE PARTS
1. Northern Lights, Inc. recommends that you keep the
following spare parts on hand for field service. The
parts are available from your local Northern Lights
dealer.
2. All owners should have the following:
a. Primary and secondary fuel filter elements
b. Oil filters
c. Air filter (industrial units only)
d. Alternator belt
e. Thermostat and gaskets
f. Glow plug
g. Injector and washer
3. If your set is operating a long distance from a
servicing dealer, add the following:
a. Complete set of injectors
b. Copper washers for injector change
c. Complete set of glow plugs
d. Fuel lift pump
Operating Procedures

ONL753W2 10/09
10
SERVICE 50 250 500 1000 2500
POINT PAGE OPERATION DAILY Hours Hours Hours Hours Hours
ENGINE:
SP1 8 & 12 Check oil level •
SP2 12 Change engine oil 1) 5) ••
SP3 12 Change lube oil filters 1) 5) ••
SP4 13 Check air cleaner 1) 4) •
SP5 13 Check V-belt tension •
SP6 13 Check valve clearances 1) 2) •
FUEL SYSTEM:
SYSTEM:
SYSTEM:
SP7 14 Check primary filter (Racor) 2) 3) •
SP8 14 Change primary filter element (Racor) 2) 3) •
SP9 14 Change secondary fuel filter 1) 3) •
SP10 15 Bleed the fuel system 3)
SP11 17 Check injectors 1) 3) 6) 7) •
SP12 17 Check fuel injection pump •
COOLING SYSTEM:
SP13 8 & 17 Check coolant level •
SP14 18 Check and flush cooling system •
SP16 18 Check and clean radiator fins •
ELECTRICAL SYSTEM:
SP18 19 Check electrolyte level in batteries •
SP19 19 Check condition of batteries with hydrometer 1) 4) •
OUT OF SERVICE:
SP20 19 Winterizing or out-of-service 3)
The Servicing Schedule Chart below shows the service schedule required for proper maintenance of your generator
set. More detailed coverage of each Service Point (SP) is listed on the page noted in the ‘page’column.
DAILY:
SP1 Check oil level in engine
SP5 Check V-belt tension
SP7 Check primary fuel filter
SP13 Check coolant level
SP18 Check electrolyte in batteries
AFTER FIRST 50 HOURS:
SP2/3 Change engine oil and filter
SP6 Adjust valves
AFTER FIRST 100 HOURS:
SP2/3 Change engine oil and filter
EVERY 250 HOURS:
SP2/3 Change engine oil and filter
SP4 Check air cleaner
SP16 Check and clean radiator
SP19 Check state of charge of batteries
EVERY 500 HOURS:
SP8 Change primary fuel filter element
SP9 Change secondary fuel filter
EVERY 1000 HOURS:
SP4 Change air cleaner element
SP6 Check valve clearances
SP11 Check injectors
EVERY 2500 HOURS:
SP12 Check fuel injection pump
SP14 Check and flush cooling system
1) Perform all maintenance once a year even if hour level has not been reached.
2) Consult manufacturer's maintenance schedule, note on chart.
3) Whenever necessary.
4) More often if necessary.
5) After first 50 hours, then after first 100 hours, then every 250 hours.
6) Clean injection nozzles every 1500 hours.
7) For EPA emission standards fuel nozzle needs to be
cleaned every 1500 hours, the fuel nozzle and fuel pump
need to be cleaned, adjusted, or repaired every 3000
hours, and the quality guarantee for these parts is 1500
hours or 2 years.
Servicing Schedule Chart

ONL753W2 10/09
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Service Record Notes

ONL753W2 10/09
12
Servicing
LUBRICATION - GENERAL
1. Use only clean, high quality lubricants stored in
clean containers in a protected area.
2. These lubricants are acceptable:
a. API Service CC/CD/CE single viscosity oils.
b. API Service CC/CD/SF multi-viscosity oils.
3. Use the proper weight oil for your average operation
temperature.
Figure 4: Lube Oils
4. Some increase in oil consumption may be expected
when SAE 5W and SAE 5-20W oils are used. Check
oil level frequently.
5. Never put additives or flushing oil in crankcase.
SP1. CHECKING OIL LEVEL
1. Check the oil level in the crankcase with the dip-
stick. The oil level must be in the waffled area
on the stick. Never allow the level to go below this
area. Follow the lubrication recommendations above.
SP2. OIL CHANGES
1. The set is delivered with special break-in oil.
Change the engine oil and oil filter after 50 hours
of operation. Use Service CC 30 weight oil during
the first 100 hours.
2. Change the oil and filter again at 100 hours using the
oil recommended in Figure 4. After this, change oil
and filter every 250 hours.
3. During intermittent cold weather operation, change
oil every 100 hours or six weeks, whichever comes
first.
4. Change oil at any seasonal change in temperature
when a new viscosity of oil is required.
5. Change oil when engine is warm.
6. Dispose of waste oil in an approved manner.
7. Never use a flushing oil.
8. Loosen the clamp on the oil change tube. Remove
cap. Drain oil. Replace the cap and tube.
9. Refill engine with recommended oil.
10. Engine capacity with new oil filter is:
3.7 quarts (3.5 liters)
SP3. CHANGING LUBE OIL FILTER
1. Change the lube oil filter every 250 hours.
2. Use a filter wrench to remove old filter. Dispose of
filter in approved manner.
3. Make sure the gasket from the old filter is removed
and discarded. Clean mount face.
4. Spread a thin film of engine oil on the rubber gasket
on the new filter and screw it on nipple until gasket
meets the sealing surface.
5. Using hands only – no wrench – tighten filter
one-half turn farther. Overtightening can do
damage to filter housing.
6. Fill engine with recommended oil. Start engine and
check for leakage. Stop engine, wait 3 minutes, and
check oil level. Add additional oil if necessary.
7. The oil filter part number is:
#24-02001
Air Single Multi-
Temperature Viscosity Viscosity
Above 32°F SAE 30W SAE 15-40W
(0°C)
-10 to 32°F SAE 10W SAE 10-30W
(-23 to 0°C)
Below -10°F SAE 5W SAE 5-20W
(-23°C)

ONL753W2 10/09
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SP4. AIR CLEANER
1. Inspect air cleaner every 250 hours. In dusty condi-
tions, check more often.
2. Industrial sets: the element cannot be cleaned.
Replace it when necessary. Part numbers are:
NL753W & W2 – #24-27301
4. NOTE: Make absolutely sure no impurities enter
the engine while changing the element. Do NOT
run the engine with the air cleaner removed.
SP5. V-BELTS
1. Check the tension and wear on the V-belt daily.
2. Use your thumb to press on the belt at the midpoint
between the crankshaft and alternator pulleys. The
tension is correct if the belt can be depressed about
3/16 in. (5 mm).
Servicing
Figure 5: Valve Adjustment
SP6. VALVE CLEARANCES
1. Adjust valve clearance after 1000 hours of operation
or as needed.
2. Valve adjustments should be done after the cylinder
head bolts have been re-tightened. Engine should be
cold and NOT running.
3. Watch the valves while turning the engine over by
hand. Turn until the inlet valve starts to open and the
exhaust valve starts to close (the valves are
rocking). Then turn the crankshaft one more full
turn and adjust the clearance on both valves for this
cylinder.
4. Loosen the lock nut and adjust the clearance between
the rocker arm and valve guide of both the intake
and exhaust valves with the adjustment screw (Figure
5). Clearance on both intake and exhaust valves
should be 0.008 in. (0.2 mm).
5. Repeat steps 3 and 4 for each cylinder. Each set of
valves must be adjusted individually.
6. Replace the rocker arm cover. Tighten cover nuts to
5 - 8 ft/lbs (0.8 - 2.3 kg/m).
Cylinder No. 1 2 3
Valve Arrangement Intake Exh. Intake Exh. Intake Exh.
When No. 1 Cylinder
is at TDC in
Compression Stroke
With the Crankshaft
turned by 3600in
normal direction from
above
Valve Sequence

ONL753W2 10/09
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Servicing
FUELS - GENERAL
1. Use only clean, high quality fuels of the following
specifications, as defined by ASTM designation
D975 for diesel fuels:
a. Use grade no. 2 diesel at ambient temperatures
above freezing 32°F (0°C).
b. Use grade no. 1 at ambient temperatures below
freezing and for all temperatures at an altitude of
above 5,500 ft. (1500 meters).
2. Use fuel having less that 1% sulphur (preferably less
that 0.5%).
3. The cetane number should be a minimum of 45.
4. DO NOT use these unsuitable grades of fuel:
a. Domestic heating oils, all types.
b. Class B engine.
c. Class D domestic fuels.
d. Class E, F, G or H industrial or marine fuels.
e. ASTM-D975-60T No. 4-D and higher number
fuels.
5. Storing fuel:
a. Keep dirt, scale, water, and other foreign matter
out of fuel.
b. Avoid storing fuel for long periods of time.
c. Fill the fuel tank at the end of each day’s
operation. This will reduce condensation.
SP7-9. FUEL FILTERS
1. Your generator set should have a primary fuel filter
installed. We recommend the Racor brand of fuel
filter-water separators.
a. Check the primary fuel filter daily as
recommended by the filter manufacturer.
Empty the collection bowl as necessary.
b. Change the element as often as necessary or
every 500 hours.
c. If the bowl fills with water, change the primary
and secondary element immediately.
2. Change secondary fuel filter every 500 hours.
a. Remove the spin-on filter by turning it
counterclockwise with a filter wrench. Fill the
new cartridge with fuel and install it after
applying engine oil to gasket surface. Screw on
until the gasket surface comes into contact with
sealing surface of filter base. Then, tighten it
two-thirds of a turn by hand. Do not overtighten.
b. The fuel filter part number is:
753W & W2 – #24-52020

ONL753W2 10/09
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Servicing
SP10. BLEEDING THE FUEL SYSTEM
CAUTION: Escaping diesel fuel under pressure can penetrate skin causing
serious personal injury. Before disconnecting lines be sure to relieve all pressure.
Before applying pressure, be sure all connections are tight and lines, pipes and
hoses aren't damaged. Fuel escaping from a very small hole can be almost
invisible. Use a piece of cardboard or wood, rather than hands, to search for
suspected leaks. If injured by escaping fuel, see a doctor at once. Serious
infection or reaction can develop if proper medical treatment isn't administered
immediately.
1. The fuel system is self-bleeding. However, any
system may need manual bleeding when:
a. A new fuel filter is installed;
b. The engine has run out of fuel;
c. The fuel lines, injection pump or any other fuel
system component has been removed and
installed.
2. Loosen bleed bolt “A” (Figure 6) on top of the filter.
Pump hand primer “B” on fuel lift pump until pure
fuel (no bubbles) escapes from bleed bolt “A”.
Tighten bleed screw “A”.
3. Loosen bleed screw “C”. Pump hand primer “B”
until pure fuel (no bubbles) escapes. Then tighten
bleed screw “C”.
4. If the engine does not start after the above bleed-
ing process, loosen a fuel line at the injector while
cranking the engine with the starter motor until pure
fuel escapes. Then tighten the connection. Do each
line one-at-a-time.
5. After the engine has started, use a piece of cardboard
to look for fuel leaks.
Figure 6: NL753 Fuel System.

ONL753W2 10/09
16
Figure 7: Remove delivery line flare nuts.
Figure 8: Remove delivery lines.
Figure 9: Remove return line nuts.
Figure 10: Remove return line.
Figure 11: Unscrew injector.
Figure 12: Remove and replace copper sealing washer.
Figure 13: Reinstall injector. Torque to proper tightness.
Servicing

ONL753W2 10/09
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SP11. INJECTOR SERVICE
1. Injectors should be checked every 1000 hours or as
needed. 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 7).
c. Remove delivery lines by disconnecting from
injectors and injection pump (Figure 8). Remove
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 (Figure 9).
Remove the return line (Figure 10).
e. Unscrew and remove the injectors (Figure 11).
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
(Figure 12). Cover holes to prevent dirt and debris
from entering the cylinders.
3. Injector installation:
a. Install a new copper sealing washer in each
injector hole (Figure 12).
b. Screw in injector and tighten to 43 or 50 ft/lbs
(6 to 7 kgm) (Figure 13).
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.
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
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.
SP13. CHECK THE COOLANT LEVEL
1. Check the coolant level each day before starting the
engine. Check the water level by removing the
pressure cap from the expansion tank or radiator.
In order to give the cooling water an opportunity to
expand, the level should be about 1 in. (2.5 cm) below
the filler cap sealing surface when the engine is cold.
2. The pressure valve in the filler cap releases when the
pressure is approximately 7 PSI (0.5 bar). Use a cap
pressure tester to check cap if you suspect it is faulty.
Servicing

ONL753W2 10/09
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Servicing
SP14. COOLING SYSTEM FLUSHING
1. Flush the cooling system every 2500 hours or every
12 months, whichever comes first.
2. Industrial sets:
Remove radiator cap and open drain cocks on radiator
and engine block. Pour clean water into radiator until
water coming from radiator is clear of discoloration.
Close the radiator drain and continue flushing until
water from engine drain is clear. Open all drain cocks
and drain completely. Close drain cock and refill with
recommended coolant mixture. Clean fins on radiator.
3. Coolant Specifications (marine and industrial):
Use 50% water / 50% ethylene glycol antifreeze
mix. Antifreeze mixture is recommended as a good
year-round coolant.
4. Check hoses and connections and repair any leakage.
SP16. CLEAN RADIATOR
1. Remove debris from radiator fins daily.
2. In very dusty applications, clean the radiator with
compressed air or steam cleaner every 100 hours.
Clean in the reverse direction of the airflow.
GENERATOR ENDS
The maintenance and operation recommendations
for the generator end are in a separate Owner’s
Manual. If you do not have one of these manuals,
contact your local Northern Lights dealer.
ELECTRICAL SYSTEM - GENERAL
1. Never switch battery switch off or break the circuit
between the alternator and batteries while the engine
is running. Regulator damage can result.
2. Do NOT reverse the polarity of battery cables when
installing the battery.
3. When welding on the unit, disconnect the regulator
and battery. Isolate the leads.
4. Disconnect the battery cables when servicing the
D.C. alternator.
5. Never test with a screwdriver, etc., against any
terminal to see if it emits sparks.
6. Do not polarize the alternator or regulator.
7. A D.C. circuit breaker protects your control panel
and wiring harness. It is located in the side of the
generator junction box.

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GLOW PLUGS
1. Each cylinder is supplied with a glow plug which
serves to heat the combustion chamber.
2. To check the glow plugs, loosen the current
carrying flat wire between the plus-poles of the
glow plugs (Figure 14). Connect a D.C. test bulb
between the plus-pole of the battery and the
plus-pole of the glow plug. If the bulb lights up,
the glow plug is functioning properly.
3. Check all glow plugs and replace any faulty ones.
Figure 14: Glow plugs.
BOOSTER BATTERIES
CAUTION: Battery gas can explode.
Keep all flames and sparks away from batteries.
1. Before changing or using booster batteries, check bat-
tery electrolyte level. Add distilled water if necessary.
2. Booster and main batteries must have the same
voltage rating.
3. First, connect positive (+) terminal of booster
battery to positive (+) terminal of main battery.
Then, connect negative (-) terminal of booster
battery to ground on the engine block (see Figure
15).
4. Remove booster battery after starting engine.
5. Sealed batteries: See manufacturer charging and
booster instructions.
SP 18-19. BATTERY CARE
1. Check electrolyte level every 50 hours or once per
month. Add distilled water to manufacturer’s
recommended level.
2. Batteries, cables and cable terminals should
be checked and cleaned every 100 hours.
Clean corrosion with a water and baking soda
solution. Flush with clean water. Tighten terminals
and grease them to inhibit corrosion.
3. Check the battery condition with a hydrometer every
250 hours.
SP20. WINTERIZING / OUT-OF-SERVICE
1. Industrial sets:
a. Drain and flush the radiator and cooling system.
Leave dry or refill with antifreeze-water mixture.
If refilling, start the engine and run to circulate
the antifreeze.
b. Fill the fuel tank or add biocide as per
manufacturer’s instructions.
c. Seal the air cleaner inlet, exhaust opening,
crankcase breather pipe, and fuel tank vent with
plastic bags and tape.
d. Store the set in a dry, protected place. If unit must
be stored outside, be sure it is well protected with
a cover.
e. Change the crankcase oil and filter.
f. Loosen the alternator belt.
g. Disconnect and clean battery. Remove to warm
storage place if possible.
h. Clean outside of unit. Paint any scratched or
chipped surfaces. Put corrosion preventative on
all exposed metal surfaces.
Figure 15:
Battery connections.
Servicing

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Troubleshooting
If you cannot correct problems with these procedures, see your Northern Lights dealer.
DC ELECTRICAL SYSTEM
PROBLEM POSSIBLE CAUSE RECOMMENDATION(S)
Battery Will Not Charge Loose or corroded connections • Clean and tighten battery connections.
Sulfated or worn out batteries • Check specific gravity of each battery.
• Check electrolyte level of each battery.
Loose or defective alternator belt • Adjust belt tension.
• Replace belt.
Starter Inoperative Check DC circuit breaker • If the breaker is tripped, reset it.
Loose or corroded connections • Clean and tighten loose battery and
harness plug connection.
Low battery output • Check specific gravity of each battery.
• Check electrolyte level of each battery.
Defective electrical system • Repair or replace.
ground wire:
Starter Cranks Slowly Low battery output • Battery is too small.
• Battery cables are too small.
Check specific gravity • Replace battery if necessary.
of each battery
Check electrolyte level • If low, fill cells with distilled water.
of each battery
Crankcase oil too heavy • Fill with oil of appropriate viscosity.
Loose or corroded connections • Clean and tighten loose connections.
Entire Electrical System Check DC circuit breaker • If breaker is tripped, reset it.
Does Not Function
Faulty connection • Clean and tighten battery and harness
plug connections.
Sulfated or worn out batteries • Check specific gravity and electrolyte
level of each battery.