Northern Lights NL773LW3 User manual

ONL773LW3
For Model: NL773LW3
OPERATOR’S MANUAL
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 ©2013 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.: ONL773LW3 11/13
As of January 2008, U.S. EPA regulations require the
application of a permanently applied label near the fuel tank
ll port for diesel driven equipment. This label is to state:
LOW OR ULTRA LOW SULFUR FUEL ONLY
Northern Lights is providing this label for application to the
fuel inlet of the fuel supply tank for each engine or generator
set. This is to be applied by the installer of the engine or gen
set, or by the manufacturer of the equipment that the engine
or gen set is installed in. The location of the label must be
in clear site of personnel that rell the supply tank.
Note: Starting in 2011, the label will state:
ULTRA LOW SULFUR ONLY.

ONL773LW3 11/13
1
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 Model
NL773LW3
INTRODUCTION ....................................................2
Models Included .................................................2
Model Numbers ..................................................2
Serial Numbers ...................................................2
WARRANTY ............................................................3
SAFETY RULES ...............................................3 - 7
LOCK OUT / TAG OUT PROCEDURES .......... 8
COMPONENT LOCATIONS
Industrial Generator ............................................9
CONTROL PANEL
S-1B Control Panel .......................................... 10
OPERATING PROCEDURES
Break-in Period.................................................11
Before Starting..................................................11
Starting..............................................................11
Operating ..........................................................11
Stopping............................................................11
Shutdowns and Alarms .................................... 12
Spare Parts ....................................................... 12
SERVICING SCHEDULE CHART .................... 13
SERVICING
Lubrication - General....................................... 14
Checking Oil.................................................... 14
Oil Changes ..................................................... 14
Changing Oil Filter .......................................... 14
Air Filter .......................................................... 15
V-Belts ............................................................. 15
Valve Clearances.............................................. 15
Fuels - General................................................. 16
Fuel Filters ....................................................... 16
Bleeding the Fuel System ................................ 17
Injector Service........................................ 18 - 19
Injection Pump................................................. 19
Cooling System - General................................ 19
Cooling System Flushing................................. 20
Clean Radiator ................................................. 20
Generator End.................................................. 20
Electrical System - General ............................. 20
Glow Plugs....................................................... 21
Booster Batteries.............................................. 21
Battery Care ..................................................... 21
Winterizing / Out-of-Service ........................... 21
TROUBLESHOOTING
Electrical .......................................................... 22
Engine ...................................................... 23 - 25
WIRING DIAGRAMS................................... 26 - 30
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 ONL773LW3 11/13
Table of Contents

ONL773LW3 11/13
2
Servicing of industrial engines and generator sets
presents unique problems. Generator sets cannot be
compared to the servicing of automobiles, trucks or
even farm equipment. Failures often occur in remote
areas far from competent assistance.
Industrial engines are often 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 amplied 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
77 mm 3
Serial Numbers
MODELS INCLUDED
This manual covers the operating instructions for:
NL773LW3 industrial generator set.
Model Numbers
Model numbers give the unit's application, block model, aspiration, and RPM:
Designates new
winding within
generator set
++
Unit Identication
Northern Lights industrial generator set with a
773 engine and PX-309K2 generator end, Tier III.
NL 773
NL773LW3
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.
=

ONL773LW3 11/13
3
A warranty registration certicate is supplied
with your set. 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.
Warranty
Safety Rules
Revised 7-10-13
NOTICE: 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.
IMPORTANT SAFETY INSTRUCTIONS.
Electromagnetic equipment, including generator sets
and their accessories, can cause bodily harm and
life threatening injuries when improperly installed,
operated or maintained. To prevent accidents be aware
of potential dangers and act safely.
READ AND FOLLOW ALL SAFETY
INSTRUCTIONS IN THIS MANUAL,
PRIOR TO THE INSTALLATION
OF ANY GENERATOR SET OR
ACCESSORY. KEEP THESE
INSTRUCTIONS FOR FUTURE
REFERENCE.
Recognize Safety Symbols and Instructions
In addition to the information found in this section, this
operator’s manual uses three different signal words to
outline potential dangers of a specic nature.
Follow All Safety Instructions
Carefully read and understand
all safety messages in this
manual and on your machine’s
safety signs. Keep signs in good
and clean condition. Replace
missing or damaged signs. Be
sure new equipment components and repair parts
include the current safety signs. For replacement signs,
proper placement of safety signs or clarication on any
safety issue, consult your Northern Lights dealer or the
factory.
There can be additional safety information contained
on parts and components from outside suppliers
that is not reproduced in this manual. Consult the
suppliers for additional safety information.
Learn how to operate the machine and how to use
the controls properly. Only trained personnel should
operate machines, or work on or around them.
Keep you machine in proper working condition.
UNAUTHORIZED MODIFICATIONS TO THE
MACHINERY MAY IMPAIR ITS FUNCTION
AND SAFETY PARAMETERS.
Prevent Bypass and Accidental Starting
!
WARNING
Do not start engine by shorting
across start terminal. Engine will
start if normal circuitry is bypassed,
creating a hazard by runaway
machinery.
Start engine only from operator’s station.
Handle Fuel Safely - Avoid Flames
!
WARNING
Diesel is highly ammable and should be treated
with care at all times. Do not refuel while smoking
or when near sparks or open ame.
ALWAYS STOP ENGINE
BEFORE FUELING
MACHINE. Always ll
portable fuel tank outdoors.
Never fuel a hot engine.
!
DANGER
!
WARNING
!
CAUTION
DANGER indicates a hazardous situation which, if
not avoided, will result in death or serious injury.
WARNING indicates a hazardous situation which, if
not avoided, could result in death or serious injury.
CAUTION indicates a hazardous situation which,
if not avoided, could result in minor or moderate
injury.

ONL773LW3 11/13
4
Safety Rules (Continued)
Revised 3-12-12
Operating equipment requires the full attention of
the operator. Do not use radio or music headphones
while operating machinery.
Practice Safe Maintenance
!
CAUTION
Understand all service procedures
before starting work. Keep area clean and dry.
Never lubricate, service, or adjust machine while it is
in operation.
Keep hands, feet and clothing away from power-
driven equipment. When shutting down an engine,
disengage all power and operator controls. Allow
the engine to cool completely before beginning any
service work.
Securely support any machinery elements that must
be raised for service work with support or lifting
machinery specically intended for that purpose.
Keep all parts in good conditions and properly
installed. Fix damage immediately. Replace any
worn or broken parts. Remove any build up of
grease, oil or debris.
Disconnect battery ground cable (-) before making
any adjustments or service work.
Stay Clear of Rotating Drivelines
!
DANGER
Entanglement in rotating drivelines can cause serious
injury or death. Keep shields in place at all times.
Make sure that rotating shields turn freely in pace
with the drivelines.
Do not wear loose tting equipment around rotating
drivelines. Stop the engine and make sure that all
moving parts have stopped
before making any adjustments,
connections, or performing
any other type of service to
the engine or other driven
equipment.
Prevent accidental discharge of starting uids by
storing all cans in a cool, safe place, away from sparks
or open ame. Store with cap securely on container.
Never incinerate or puncture a fuel container.
Prevent res by keeping machine clean of accumulated
trash, grease and debris. Always clean any spilled fuel
as swiftly as possible. Do not store oily rags, which
can ignite and burn spontaneously.
Be prepared if a re starts. Keep a rst aid kit and re
extinguisher handy. Keep emergency contact numbers
for re department, doctors, ambulance and hospital
near the telephone.
Service Machines Safely
!
DANGER
Do not wear a necktie, scarf,
necklace, rings or other
jewelry, or any loose clothing
when working near moving
parts. Tie long hair behind your head. If any of these
items get caught in moving machinery, severe injury or
death could result.
Check for any loose electrical connections or faulty
wiring.
Look completely around engine to make sure that
everything is clear before starting.
Wear Protective Clothing
!
WARNING
To prevent catching anything in moving machinery,
always wear close tting clothes and safety equipment
appropriate to the job.
Prolonged exposure to loud noise can cause hearing
loss or impairment.
Wear suitable authorized
hearing protection, such
as earmuffs or plugs to
protect against loud noises.

ONL773LW3 11/13
5
Safety Rules (Continued)
Revised 3-12-12
Install all Safety Guards
!
WARNING
Direct contact with rotating
fans, belts, pulley and drives
can cause serious injury.
Keep all guards in place at all
times during engine operation.
Wear close-tting clothes. Stop the engine and be
sure all fans, belts, pulleys and drives are stopped
before making adjustments, connections, or cleaning
near fans and their components.
Do not allow anything on your person to dangle into
or come in contact with a moving fan, belt, pulley or
drive. Fans can act as vacuums and pull materials
up from below, so avoid that area as well while in
service.
Safe Battery Handling
!
WARNING
Prevent Battery Explosions
Battery gas is highly
ammable. Battery
explosions can cause severe
injury or death. To help
prevent battery explosions, keep sparks, lighted
matches and open ame away from the top of battery.
When checking battery electrolyte level, use a
ashlight.
Never check battery charge by contacting the posts
with a metal object. Use a volt-meter or hydrometer.
Frozen batteries may explode if charged. Never
charge a battery that has not been allowed to warm to
at least 16oC (60oF).
Always remove grounded (-) battery clamp rst and
replace ground clamp last.
S ulfuric acid in battery electrolyte is poisonous and
strong enough to burn skin, eat holes into clothing and
other materials, and cause blindness if splashed into eyes.
To Avoid Hazards:
• Fill batteries only in well-ventilated areas.
• Wear appropriate eye protection and rubber gloves.
• Never use air pressure to clean batteries.
• Wear appropriate ventilation equipment to avoid
inhaling fumes when adding electrolyte.
• Do not spill or drip electrolyte.
• Use correct jump-start procedure if required.
If acid is spilled on skin or in eyes:
1. Flush skin with water.
2. Apply baking soda or lime to
help neutralize acid.
3. Flush eyes with water for
15-30 minutes.
4. Get medical attention
immediately.
If acid is swallowed:
1. DO NOT induce vomiting.
2. Drink large amounts of
water or milk, without
exceeding 2 liters
(2 quarts)
3. Get medical attention
immediately
Battery posts, terminals, and related accessories
can contain lead and lead compounds, chemicals
known to the State of California to cause cancer and
reproductive harm. Wash hands after handling.
Handle Chemical Products
Safely
!
WARNING
Direct exposure to hazardous
chemicals can cause serious
injury. Among the potentially
hazardous chemicals that may be used
with Northern Lights products are lubricants,
coolants, paints and adhesives.
All potentially hazardous chemicals come with a Material
Data Safety Sheet (MSDS). The MSDS provides specic
details on chemical products, including physical hazards,
safety procedures and emergency response techniques
!
WARNING

ONL773LW3 11/13
6
Safety Rules (Continued)
Revised 3-12-12
Read and understand the MSDS for each chemical before
you start any job that includes it. Follow the procedures
and use appropriate equipment exactly as recommended.
Contact your Northern Lights dealer or Northern Lights
factory for MSDS’s used on Northern Lights products.
Work in Well Ventilated Areas
!
CAUTION
Exhaust fumes from engines contain carbon monoxide
and can cause sickness or death. Work in well ventilated
areas to avoid prolonged exposure to engine fumes. If it
is necessary to run an engine in an enclosed area, route
the exhaust fumes out of the area with an approved, leak
proof exhaust pipe extension.
Remove Paint Before Welding or Heating
!
WARNING
Hazardous fumes can be generated
when paint is heated by welding,
soldering or using a torch. To avoid
potentially toxic fumes and dust,
remove paint before heating.
• Remove paint a minimum of 100
mm (4 in.) from the
area that will be affected by heat.
• If paint cannot be removed, wear an approved respirator.
• If you sand or grind paint, use an approved respirator.
• If you use solvent or paint stripper, remove stripper
with soap and water before welding. Remove
solvent or paint stripper containers from the area.
• Allow at least 15 minutes for fumes to disperse
before welding or heating.
Do not use a chlorinated solvent in an area where welding
will occur. Work only in areas that are well ventilated.
Dispose of paint and solvent properly.
Service Cooling System Safely
!
WARNING
Opening a pressurized cooling
system can release explosive
uids and causing serious burns.
Before opening any pressurized
cooling system, make sure the
engine has been shut off. Do not remove a ller cap
unless it is cool enough to comfortably grip with bare
hands. Slowly loosen cap to relieve pressure before
opening fully.
Avoid High Pressure Fluids
!
WARNING
Relieve pressure prior to
disconnecting pressurized lines.
Escaping uid under pressure
can penetrate the skin causing
serious injury. Always relieve pressure before
disconnecting hydraulic or other pressurized lines.
Tighten all connections rmly before re-applying
pressure.
If searching for leaks, use a piece of cardboard.
Always protect your hands and other body parts from
high-pressure uids.
If an accident occurs, see a doctor immediately. Any
high pressure spray injected into the skin must be
removed within a few hours to prevent the risk of
gangrene or other infection.
Avoid Heating Near Pressurized Fluid Lines
!
WARNING
Flammable spray can be generated
by heating near pressurized uid
lines, resulting in severe burns and
bodily injury. Pressurized lines
can rupture when heat goes beyond the immediate
ame area. Do not weld, solder or use a torch or
open ame near pressurized lines or other ammable
uids.
Do Not Open High-Pressure Fuel System
!
DANGER
Many Northern Lights engines use high-pressure
fuel injection. High-pressure uid remaining in fuel
lines can cause serious injury. Do not disconnect or
attempt any repair of fuel lines, sensors, or other

ONL773LW3 11/13
7
Safety Rules (Continued)
Revised 3-12-12
material containing asbestos. Keep all bystanders
away from any area where asbestos dust may be
generated.
Use Proper Lifting Equipment and Techniques
!
WARNING
Lifting heavy components incorrectly
can cause severe injury or damage
to machinery. Avoid unbalanced
loads. Do not use lifting eyes. Lift the
generator set using lifting bars inserted
through the lifting holes on the skid.
Follow all recommended removal and installation
procedures in this and associated Northern Lights
manuals.
Use Proper Tools
!
CAUTION
Makeshift tools and procedures
can create safety hazards.
Always use appropriate tools for
the job.
Use power tools only to loosen threaded parts and
fasteners. For loosening and tightening hardware,
always use the correct sized tools.
Do not use US measurement tools on metric
fasteners, or vice versa. Use only service parts that
meet Northern Lights specications.
Dispose of Waste Properly
!
CAUTION
Disposing of waste improperly can threaten the
environment and lead to unsafe working conditions.
Potentially harmful waste used in Northern Lights
equipment can include oil, fuel, coolant, lters and
batteries.
Use leakproof containers to drain uid. Do not
use food or beverage containers that may mislead
someone into drinking from them.
Do not pour waste onto the ground, down a drain or
into any water source.
components between the high-pressure fuel pump
and nozzles on engines with high pressure fuel
systems.
ONLY AUTHORIZED TECHNICIANS
CAN PERFORM REPAIRS ON AN HIGH
PRESSURE FUEL INJECTION SYSTEMS.
Avoid Hot Exhaust
!
WARNING
Avoid exposure to and physical
contact with hot exhaust
gases. Exhaust parts and streams can reach high
temperatures during operation, leading to burns or
other serious injury.
Cleaning exhaust lters can also lead to exposure to
hot exhaust gas and the injury risk associated with
it. Avoid exposure to and physical contact with hot
exhaust gases when cleaning exhaust lters.
During auto or manual/stationary exhaust lter
cleaning operations, the engine will run at
elevated temperatures for an extended period of
time. Exhaust parts and streams can reach high
temperatures during operation, leading to burns or
other serious injury.
Avoid Harmful Asbestos Dust
!
WARNING
Inhaling asbestos bers may cause
lung cancer. Avoid breathing any
dust that may be generated when
handling components containing
asbestos bers, including some
gaskets.
The asbestos used in these components is usually
found in a resin or otherwise sealed. Normal
handling of these components is not dangerous,
as long as airborne dust containing asbestos is not
generated.
Avoid creating dust. Never use compressed air for
cleaning. Avoid brushing or grinding materials
containing asbestos. When servicing, wear an
approved respirator. A special vacuum cleaner is
recommended to clean asbestos. If this vacuum is
not available, apply a mist of oil or water on the

ONL773LW3 11/13
8
General Policy
To avoid dangerous or hazardous situations, refrain from
any of the following:
• Removing or bypassing a guard or other safety device
• Placing any part of your body in a position where you
could be caught by moving machinery.
• Cleaning or oiling machinery when in operation.
• Adjusting circuits, chillers, pumps, air handlers, valves,
circuit breakers or fans while in operation.
• Working on piping or high pressure systems.
Lock Out/Tag Out Instructions -
Electrical Equipment
Be sure the equipment’s ON/OFF switch is in the OFF
position and is unplugged from any electrical source before
attempting to perform any type of work on the equipment.
Obtain an electrical plug cap cover with a lockset. Secure
the plug terminal end using the electrical plug lockout cap.
Lock the cap and retain the key.
If the equipment is directly wired into an electrical box with
a shut off switch, obtain a lock pad and/or the appropriate
colored tags and place the lock and tag through the shut
off lever. Retain the key until the repair is completed and
the machine is safe to start. Be certain the shut off lever
is in the OFF position before restarting. NEVER give a
lock out key to unauthorized personnel.
If the equipment is directly wired into an electrical box
without a shut off switch and lock out capability, then a
circuit breaker lock out will be required. Obtain a circuit
lock and tag set. Install the lock onto the circuit breaker
box. Ensure the unit ON/OFF switch is in the OFF position
before restarting.
Lock Out/Tag Out Instructions -
Pneumatic and Hydraulic Equipment
For servicing pneumatic and hydraulic equipment, the
following additional procedures must be implemented,
following completion of lock out/tag out procedures for
the unit to be serviced:
Shut off air, water or supply valves at the equipment to
be serviced.
Check the local bleed-off point for completed release of
pressurized air, water or oil.
If shutting off of air, water or other material cannot be
achieved at the local supply valve, shut off valves further
back in the system and re-check the bleed-off point until
complete shut-off is achieved.
Afx a DO NOT OPERATE tag to each valve handle that
requires shut off. Each DO NOT OPERATE tag must be
signed and dated by the authorized technician servicing
the equipment.
Lock Out/Tag Out Instructions -
Air Hose Connected Pneumatic Equipment
Equipment connected to the compressed air system
through an air hose with a detachable tting must be
shutdown and unplugged. Excess air must be bled prior
to removing the air hose, prior to any maintenance or
repair activities.
Afx a DO NOT OPERATE tag to the air hose near the
detachable tting. Each DO NOT OPERATE tag must be
signed and dated by the authorized technician servicing
the equipment. Check that the equipment cannot be
operated by activating the ON switch.
Stored Energy
Immediately after applying Lock Out or Tag Out devices,
ensure that all potentially hazardous stored or residual
energy is relieved, disconnected, restrained and otherwise
rendered safe.
Verication of Isolation
Verify the machinery or equipment is actually isolated and
de-energized prior to beginning work on a machine or on
equipment that has been locked out.
Restarting Procedures
Follow the procedures below prior to restoring energy:
• Ensure that all machinery or equipment is properly
reassembled. Inspect the machinery or equipment to
verify non-essential items have been removed.
• Ensure that all personnel are safely outside danger
zones. Notify personnel that lock out/tag out devices have
been removed and energy will be reapplied.
• Only authorized personnel may remove lock out/tag out
devices or notices.
Scope
During maintenance, repairs or retooling of a Northern Lights generator set, simply turning the machine off or unplugging
it while it is being worked on does not give enough protection to others who are not performing the maintenance or
repair. Many serious accidents happen when someone thought the machine was turned off, or all of its energy was
safely blocked or released.
!
CAUTION
!
WARNING
!
WARNING
!
WARNING
!
WARNING
!
CAUTION
!
CAUTION
Lock Out / Tag Out Procedures
Added 3-12-12

ONL773LW3 11/13
9
Industrial Generator Component Locations
13. Hourmeter
14. Control Panel
15. Starter
16. Alternator
17. Radiator Shroud
1. Junction Box
2. Air Filter
3. Crankcase Vent
4. Lube Oil Fill
5. Coolant Fill
6. Injection Pump
Figures 2-A and B: NL773LW3
7. Fuel Lift Pump
8. Dipstick
9. Fuel Inlet and Return
10. Oil Filter
11. Block Water Drain
12. Secondary Fuel Filter
1
23 4 5
6
7
8
9
10
11
12
13
14
15
16
17

ONL773LW3 11/13
10
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.
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 has a light that glows when
the set is running.
3. HOUR METER
Keeps track of engine running time.

ONL773LW3 11/13
11
BREAK-IN PERIOD
1. The rst 100 hours on a new or reconditioned
engine are critical to its life and performance.
2. Operate the engine under various conditions,
particularly heavy loades with minimal idling, to
help seat engine components properly.
3. Constantly check the engine temperature and oil
pressure.
4. Oil consumption is greater during break-in as
piston rings take time to seat.
5. Break-In Oil Changes: Change engine oil and
lter at 50 hours. Change oil and lter again at
250 hours (consult Lubricants section for oil
recommendation).
BEFORE STARTING
1. 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 ller
cap sealing surface when the engine is cold.
CAUTION: Use protective clothing and open the ller
cap carefully when the engine is warm to prevent
burns.
2. Check the oil level in the crankcase with the
dipstick. The oil level must be in the wafed 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 rst
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 ve 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.
SHUTDOWNS AND ALARMS
1. Generator sets have shutdown systems to stop the
engine in the event of high water temperature or low
Operating Procedures
Updated 1-10-13

ONL773LW3 11/13
12
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 21 to
isolate the cause of the overheat.
CAUTION: Do not remove the water ll
cap of an overheated engine. Escaping high tem-
perature 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, ll 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 recommends that you keep the
following spare parts on hand for eld service. The
parts are available from your local Northern Lights
dealer.
2. All owners should have the following:
 a. Primaryandsecondaryfuellterelements
 b. Oillters
 c. Airlter
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

ONL773LW3 11/13
13
SERVICE 50 200 500 1000 2500
POINT PAGE OPERATION DAILY Hours Hours Hours Hours Hours
ENGINE:
SP1 8& 12Check oil level •
SP2 12Change engine oil 1) 5) •
SP3 12 Change lube oil lters 1) 5) ••
SP4 13Check air cleaner 1) 4) •
SP5 13Check V-belt tension •
SP6 13Check valve clearances 1) 2) •
FUEL SYSTEM:
SP7 14 Check primary lter (Racor) 2) 3) •
SP8 14 Change primary lter element (Racor) 2) 3) •
SP9 14 Change secondary fuel lter 1) 3) •
SP10 15 Bleed the fuel system 3)
SP11 17Check injectors 1) 3) 6) 7) •
SP12 17Check fuel injection pump 7) •
COOLING SYSTEM:
SP13 8 & 17 Check coolant level •
SP14 18 Check and ush cooling system •
SP16 18 Check and clean radiator ns •
ELECTRICAL SYSTEM:
SP18 19Check electrolyte level in batteries 1) 4) •
SP19 19Check condition of batteries with hydrometer 1) 4) •
OUT OF SERVICE:
SP2019Winterizing 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 lter
SP13 Check coolant level
SP18 Check electrolyte in batteries
AFTER FIRST 50 HOURS:
SP2/3 Change engine oil and lter
SP6 Adjust valves
AFTER FIRST 100 HOURS:
SP2/3 Change engine oil and lter
EVERY 200 HOURS:
SP2/3 Change engine oil and lter
SP4 Check air cleaner
SP16 Check and clean radiator
SP19 Check state of charge of batteries
EVERY 500 HOURS:
SP2/3 Change engine oil and lter
SP8 Change primary fuel lter element
SP9 Change secondary fuel lter
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 ush 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 rst 50 hours, then after 100 hours, then at 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
Updated 7-9-13

ONL773LW3 11/13
14
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 ushing 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 wafed 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 lter after 50 hours
of operation. Use Service CC 30 weight oil during
the rst 100 hours.
2. Change the oil and lter again at 100 hours using the
oil recommended in Figure 4. After this, change oil
and lter every 200 hours.
3. During intermittent cold weather operation, change
oil every 100 hours or six weeks, whichever comes
rst.
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 ushing oil.
8. Loosen the clamp on the oil change tube. Remove
cap. Drain oil. Replace the cap and tube.
9. Rell engine with recommended oil.
10. Engine capacity with new oil lter is:
4.8 quarts (4.5 liters)
SP3. CHANGING LUBE OIL FILTER
1. Change the lube oil lter every 200 hours.
2. Use a lter wrench to remove old lter. Dispose of
lter in approved manner.
3. Make sure the gasket from the old lter is removed
and discarded. Clean mount face.
4. Spread a thin lm of engine oil on the rubber gasket
on the new lter and screw it on nipple until gasket
meets the sealing surface.
5. Using hands only – no wrench – tighten lter
one-half turn farther. Overtightening can do
damage to lter 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 lter 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)
Updated 7-9-13

ONL773LW3 11/13
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SP4. AIR CLEANER
1. Inspect air cleaner every 200 hours. In dusty
conditions, check more often.
2. Industrial sets: the element cannot be cleaned.
Replace it when necessary. Part numbers are:
NL773LW3 – #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
Updated 7-9-13

ONL773LW3 11/13
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Servicing
FUELS - GENERAL
1. Use only clean, high quality fuels of the following
specications, as dened 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. Biodiesel:
Biodiesel involves the transesterication of vegetable oils
or animal fats. It can involve animal fats, yellow greases
(used greases), cotton seed, sunower seed, coconut oil, or
sesame seed, but mainly in the US soybean methyl ester is
used (SME). In Europe mainly rapeseed (canola) methyl
ester is made (RME), and in Asia palm methyl ester (PME)
is made. 100% biodiesel (B100) is made in compliance
with ASTM D6751 or EN14214 (EU)
specications.
Biodiesel may be used in a 5% blend (5% biodiesel/ 95%
diesel) from a BQ-9000 accredited producer. 20% biodie-
sel blends (20% biodiesel/ 80% diesel) can only be used if
they meet ASTM D6751 or EN14214 (EU)
specications. A 2% reduction in power and a 3%
reduction in fuel economy can be expected if a 20% blend
is used. With a 20% biodiesel blend, an approved fuel
conditioner is recommended. The petroleum part of the
biodiesel blend must meet ASTM D975 or EN590 (EU)
specications. Biodiesel blends must be used within 90
days of their manufacture. When biodiesel blends are used
the oil level must be checked daily and storage, leaking,
possible microbial growth, plugging, and components
degradation must all be checked more frequently.
Note: Using raw pressed or partially rened vegetable
oils or recycled greases as fuel (which have not been
through transesterication) could cause engine failure.
Request a certicate of analysis from an approved
biodiesel fuel distributor to make sure the biodiesel blend
meets specications.
6. 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 lter
installed. We recommend the Racor brand of fuel
lter-water separators.
a. Check the primary fuel lter daily as
recommended by the lter manufacturer.
Empty the collection bowl as necessary.
b. Change the element as often as necessary or
every 200 hours.
c. If the bowl lls with water, change the primary
and secondary element immediately.
2. Change secondary fuel lter every 250 hours.
a. Remove the spin-on lter by turning it
counterclockwise with a lter 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 lter base. Then, tighten it
two-thirds of a turn by hand. Do not overtighten.
b. The fuel lter part number is:
773LW3 – #24-52020

ONL773LW3 11/13
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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 lter 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 lter.
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: The Fuel System - the NL773LW3 varies slightly from this depiction

ONL773LW3 11/13
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Figure 7: Remove delivery line are 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
For illustration purposes only - the NL773LW3 may look a little different.