Northern Lights Lugger M773LW3 User manual

OPERATOR’S MANUAL
OPERATOR’S MANUAL
OM773LW3
For Model: M773LW3 and M773LW3G
www.northern-lights.com

Breathing Diesel engine exhaust and some of its constituents
are known to the State of California to cause cancer, birth
defects, and other reproductive harm.
* Always start and operate the engine in a well-ventilated area.
* If in an enclosed area, vent the exhaust to the outside.
* Do not modify or tamper with the exhaust system.
* Do not idle the engine except as necessary.
For more information, go to www.P65warnings.ca.gov/diesel.
— CALIFORNIA —
Proposition 65 Warning:
Northern Lights
4420 14th Avenue NW
Seattle, WA 98107
Tel: [phone]
Fax: [phone]
Copyright ©2019 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.: OM773LW3 11/20

OM773LW3 11/20
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
M773LW3 and M773LW3G
INTRODUCTION ..................................................2
Models Included .................................................2
 UnitIdentication...............................................2
 SerialNumbers ...................................................2
WARRANTY ...........................................................3
SAFETY RULES..............................................3 - 7
LOCK OUT / TAG OUT PROCEDURES .......... 8
COMPONENT LOCATIONS
M773LW3GMarineGenerators...................... 10
 M773LW3MarineGenerators..........................11
CONTROL PANELS
Series 1-B......................................................... 12
Series 3............................................................. 12
Series 4............................................................. 12
OPERATING PROCEDURES
 Break-inPeriod................................................ 13
 BeforeStarting................................................. 13
 Starting............................................................. 13
 Operating ......................................................... 13
 Stopping........................................................... 13
 ShutdownsandAlarms .................................... 14
 SpareParts ....................................................... 14
SERVICING SCHEDULE CHART ................. 15
SERVICING
 Lubrication-General....................................... 16
 CheckingOil.................................................... 16
 OilChanges ..................................................... 16
 ChangingLubeOilFilter................................. 16
 AirCleaner....................................................... 17
V-Belts ............................................................. 17
 ValveClearances.............................................. 17
 Fuels-General................................................. 18
 FuelFilters ....................................................... 18
 CoolingSystem-General................................ 19
 Checkingcoolantlevel ................................... 19
 CoolingSystemFlushing................................. 19
 InjectorService................................................ 20
 InjectionPump................................................. 20
 HeatExchanger............................................... 22
 RawWaterPump ............................................. 22
 ExhaustElbow ................................................ 22
 GeneratorEnds ................................................ 22
 ElectricalSystem-General ............................. 22
 GlowPlugs....................................................... 22
 BoosterBatteries.............................................. 23
 BatteryCare ..................................................... 23
 Winterizing/Out-of-Service ........................... 23
TROUBLESHOOTING
 Electrical .......................................................... 24
 Engine ...................................................... 25 - 27
 BleedingtheFuelSystem ................................ 28
WIRING DIAGRAMS (Current Production)
 ACElectrical ........................................... 30 - 33
DCElectrical ........................................... 34 - 42
 PanelWiring ............................................ 43 - 45
APPENDIX (Non-Current Production Diagrams)
 DCElectrical ........................................... 46 - 49
 PanelDiagrams........................................ 50 - 54
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OM773LW311/20
Table of Contents

OM773LW3 11/20
2
Servicingofmarineenginesandgeneratorsets
presentsuniqueproblems.Inmanycasesboats
cannotbemovedtoarepairfacility.Marineengines
cannotbecomparedtotheservicingofautomobiles,
trucksorevenfarmequipment.Failuresoftenoccur
inremoteareasfarfromcompetentassistance.
Marineenginesaretaxedfarmoreseverelythan
autoortruckengines;therefore,maintenancesched-
ulesmustbeadheredtomorestrictly.
Failuresbeginwithminorproblemsthatareover-
looked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
L, W, G, 3
M - Northern Lights marine
generator set
Model number of engine block
Bore Cylinders
77 mm 3
MODELS INCLUDED
Thismanualcoverstheoperatinginstructionsfor:
M773LW3 and M77LW3G marine generator setsthe
unit'application,blockmodel,aspiration,andRPM:
L- Long stroke
W- Auxiliary Winding in Generator
End
G- GEM series base frame
3 - US EPA Tier III compliant
++
Northern Lights marine generator set with a 773 engine, PX-309K2 generator end, AVR, US EPA Tier III.
M 773
M773LW3 =
Yoursethasthreeserialnumbers:1anenginenumberstamped
ontheblock,2 ageneratorplate,and3a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.
Unit Identication
Serial Numbers
Model numbers give the unit’s application, block model, aspiration, and RPM
Northern Lights marine diesel generator set with a 773 engine, PX-309K2 generator end, GEM series,
US EPA Tier III.
M773LW3G =
Updated 7-6-18

OM773LW3 11/20
3
Awarrantyregistrationcerticate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.
Safety Rules
Warranty
Updated 8-14-19
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dierent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.
!
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.
DANGER: Northern Lights generator sets and /or any other diesel powered equipment provided by NLI is not provided
with ignition protected components, and therefore is not to be installed in the presence of combustible gases having a
ash point of 43.3 Degrees C (110 Degrees F) or lower, such as Gasoline, Propane, Natural Gas or other similar fuel
sources.

OM773LW3 11/20
4
Safety Rules (Continued)
Updated 4-12-17
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earmusorplugstoprotectagainstloud
noises.
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.
Handle Fuel Safely - Avoid Flames
!
WARNING
Dieselishighlyammableandshouldbetreatedwith
careatalltimes.Do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.
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.

OM773LW3 11/20
5
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.
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.
Safety Rules (Continued)
Updated 4-12-17
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.
!
WARNING

OM773LW3 11/20
6
Safety Rules (Continued)
Updated 4-12-17
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o.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.
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
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aected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.

OM773LW3 11/20
7
Safety Rules (Continued)
Updated 4-12-17
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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.
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
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.

OM773LW3 11/20
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 o󰀨 switch, obtain a lock pad and/or the appropriate
colored tags and place the lock and tag through the shut
o󰀨 lever. Retain the key until the repair is completed and
the machine is safe to start. Be certain the shut o󰀨 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 o󰀨 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 o󰀨 air, water or supply valves at the equipment to
be serviced.
Check the local bleed-o󰀨 point for completed release of
pressurized air, water or oil.
If shutting o󰀨 of air, water or other material cannot be
achieved at the local supply valve, shut o󰀨 valves further
back in the system and re-check the bleed-o󰀨 point until
complete shut-o󰀨 is achieved.
A󰀩x a DO NOT OPERATE tag to each valve handle that
requires shut o󰀨. 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.
A󰀩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 o󰀨 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 o󰀨, or all of its energy was
safely blocked or released.
!
CAUTION
!
WARNING
!
WARNING
!
WARNING
!
WARNING
!
CAUTION
!
CAUTION
Lock Out / Tag Out Procedures
Updated 4-12-17

OM773LW3 11/20
9
Notes

OM773LW3 11/20
10
Figure 1 (right): Service side M773LW3G
(S/N: 7732-54637 and above)
17
2 4
35
6
78
10
9
11
12
14
15
16
13
18
19
Marine Generator Component Locations
Figure 2 (left): Non-service side
M773LW3G (S/N: 7732-54367 and above)
20 2021 22 23
25
26
1. Generator control box
2. Coolant recovery bottle
3. Fuel lter
4. Air lter housing
5. Fuel lift pump
6. Fuel injector
7. Lube oil ll, top
8. Coolant ll
9. Injection pump
10. Stop solenoid
11. Lube oil ll, side
12. Sea water pump
13. Lube oil drain
14. Oil dipstick
15. Oil lter
16. Fuel manifold
17. Control panel plug
18. AC circuit breaker for AVR
19. DC circuit breaker
20. Heat exchanger end caps
21. Expansion tank
22. Starter
23. Exhaust elbow
24. Vibration mount
25. Alternator
26. Belt guard
24
1
Updated 10-19-20

OM773LW3 11/20
11
Marine Generator Component Locations
Updated 10-19-20
17
1
345
6
7
8
10
9
11
12
15
16 14 13
18
19
2
1. Generator control box
2. Coolant recovery bottle
3. Fuel lter
4. Air lter housing
5. Fuel lift pump
6. Fuel injector
7. Lube oil ll, top
8. Coolant ll
9. Injection pump
10. Stop solenoid
11. Lube oil ll, side
12. Sea water pump
13. Lube oil drain
14. Fuel manifold
15. Oil dipstick
16. Fuel lter
17. Control panel plug *
18. AC circuit breaker for AVR
19. DC circuit breaker
20. Heat exchanger end caps
21. Expansion tank
22. Starter
23. Exhaust elbow
24. Vibration mount
25. Alternator
26. Belt guard
Figure 3 (right): Service side M773LW3
(up to S/N: 7732-54636)
20 2021 22 23
25
26
24
Figure 4 (left): Non-service side M773LW3
(up to S/N: 7732-54636)
* Shown with round “Merc” style plug. Plug type may vary.

OM773LW3 11/20
12
Figure 6: Series 3 Generator Control Panel
Control Panels
Figure 5: Series 1-B Generator Control Panel
1. SHUTDOWN BYPASS-PREHEAT SWITCH
Therearetwofunctionsbuiltintothisswitch:
 1.Preheatsthefuelbeforebeginningthestarting
 process.Pressswitch10secondsbefore
 attemptingstart-up.
 2.Bypassesthesafetyshutdownfeatureduring
startingprocess.Keepswitchengagedwhilestarting
engineandforuptovesecondsafterwards,allowing
oilpressuretobuildbeyondshutdownsetpoint.
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 muer systems can cause engine
damage.
 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.
4. OIL PRESSURE GAUGE
Showstheoilpressureintheenginelubricatingsystem.
5. WATER TEMPERATURE GAUGE
Registersthetemperatureofthecoolingwater.
6. D.C. VOLTMETER OR AMMETER
Whentheengineisstopped,thevoltmeterindicatesthe
conditionofthebattery.Whentheengineisrunning,
thevoltmeterindicatesthevoltageoutputofthe
alternator.
Updated 8-14-19

OM773LW3 11/20
13
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loadstohelpseatengine
componentsproperly.50%loadisrequired;75%is
preferred.
3. Constantlychecktheenginetemperatureandoil
pressuregauges(setswithSeries3or4panels).
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
 100hours,thenatevery200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expansiontankshouldbefull.Overowbottle
shouldbehalffull.
Do not open the ller cap when the engine is
warm. Opening a warm ller cap can cause
severe burns.
2. Checktheoillevelinthecrankcasewiththe
 dipstick.Theoillevelmustbeinthewa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.Donotremovedipstickwhenengine
isrunning.
3. Checkthefueltanklevelandopenanyfuelvalves.
4. Checkandcleantheseastrainerandreopenthesea-
cock.
5. PlacethebatteryswitchintheONposition.
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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thestartswitch
andcontinuetoholdthebypass/preheatswitchfor
uptoveseconds.Donotcrankthestarterformore
than10secondsconsecutively.Iftheenginefailsto
startwiththerstattempt,besurethatithasstopped
completelybeforere-engaging.
NOTE: Excessive cranking of the starter on Marine
sets equipped with a water lift muer can cause
engine damage. If the engine does not start after three
10-second cranks, close the sea-cock, and remove the
impeller from the raw water pump. This will prevent
the muer from lling with water and backlling the
exhaust line and engine. Once the engine starts, shut
it o immediately and re-install the impeller and open
the sea-cock. Re-start the engine and check the exhaust
overboard outlet for gushes of water.
OPERATING
1. UnitswithSeries3ControlPanels:checkgauges
often.Oilpressuremustbeabove15PSI.TheD.C.
voltmetershouldreadbetween11and15voltsat80°F
(25°C)ambienttemperature.Thecoolanttemperature
gaugemustbebetween167°Fand194°F(75°Cto
90°C).ChecktheA.C.voltageandfrequencymeters
(Series4panel).Ifthegaugesdeviatefromnormal
levels,shutdownthegeneratorsetandinvestigate.
2. Afterstarting,addelectricalloadupto50%forrst
fewminutes.Loadnormallyafter5minutes.
STOPPING
1. Removeelectricalloadfromthegeneratorset.
2. Runtheenginefora3to5minutecooldownperiod.
3. MovetheEngineControlswitchtotheSTOPposition
momentarily.
4. Closethesea-cock,fuelvalve,andbatteryswitch.
Operating Procedures
Updated 10-19-20
!
DANGER

OM773LW3 11/20
14
SHUTDOWNS AND ALARMS
1. Generatorsetshaveshutdownsystemstostopthe
engineintheeventofhighwatertemperature,lowoil
pressureorhighexhausttemperature.
 a. Otheralarmsandshutdownsareavailableas
optionalequipment.
Contact your Northern Lights dealer for
troubleshooting assistance if not equipped with
optional gauge panels.
2. Ifoptionalgaugepanelsareinstalled,dothe
followingwhenyourwarningorshutdownsystemis
activated:
 a. Engagethepreheatswitchtocheckthetemperature
gauge,ifinstalled.
 b. Ifabove205°F(96°C),usetheTroubleshooting
 Guideonpage32toisolatethecauseofthe
  overheat.
Do not open the ller cap when the engine is
warm. Opening a warm ller cap can cause
severe burns.
 c.Makerepairs.Restartyourgeneratorsetafterthe
  temperaturegaugeregistersbelow200°F(94°C).
 d. Watchthetemperaturegaugeregularlyand
  turnotheunitifthetemperaturerisesabove
  205°F(96°C)onMarineunits.Repeattrouble-
  shooting.
3. Ifshutdownisactivatedandthetemperaturegauge
showstemperaturewithinnormaltemperaturerange:
 a. Thisshutdowncouldhavehappenedbecauseof
 atoohighexhausttemperature.Thiscouldhave
 beencausedbyadamagedimpellerorapartially
 blockedseawaterstrainer.Checktheseawater
 strainerrst.Ifitisclear,thencheckthe
  conditionoftheseawaterpumpimpeller.
 b. Checktheenginecrankcaseoillevel.
 c. Iftheoillevelislow,llwithrecommended
  lubricatingoilandrestart.Watchtheoilpressure
  gaugecarefullyandshutotheengineifitdoes
  notshowanormalreading(20-60PSI)aftera
  fewsecondsofoperation.
 d. Iftheoillevelisnormal,DONOTrestartthe
  engine.Callyourdealerforassistance.
SPARE PARTS
 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.Marinemodelshaveoptional“On-Board-
Kits,”ahandyboxthatcontainsthemostcommon
partsyouwillneed.
 NorthernLightsstandardsparepartskit(P/N
38-08605)*
 contains:
 a. Primaryandsecondaryfuellterelements
 b. Oillters
 c. Airlterelement
 d. Drivebelt
 e. Thermostatandgaskets
f. Raw waterpumpimpellerwithgaskets
 g.Waterpumpcovero-ring
 h. Rockerarmcovergasket
 Intendedforlong-distancecruisers,NorthernLights
worldclasssparepartskit(P/N38-08612)*contains:
 a. Primaryandsecondaryfuellterelements
 b. Oillters
 c. Airlterelement
 d. Drivebelt
 e. Thermostatandgaskets
f. Raw waterpumpimpellerwithgaskets
 g.Waterpumpcovero-ring
 h. Rockerarmcovergasket
 i. Impellerkitwithgasket
 j.Injectorassembly
 k. 12vglowplug
 l.Gasketset
 m.Fuelliftpumpandmtg.gasket
 n.O-ring
 o.Relay,SPDT12v50A
 p.Workshopmanual
Operating Procedures
Updated 8-14-19
!
DANGER
*-ForusewithM773LW3andM773LW3Ggeneratorsetswithheat
exchangers.ConsultyourNorthernLightsdealerforyourunit’s
specicsparepartsrequirements.

OM773LW3 11/20
15
Servicing Schedule Chart
Updated 8-14-19
After After Every Every Every Every Every
SERVICE 50 100 100 200 500 1000 2500
POINT PAGE OPERATION DAILY Hours Hours Hours Hours Hours Hours Hours
ENGINE:
SP1 16Check oil level •
SP2 16Change engine oil 1) 4) •• •
SP3 16 Change lube oil lters 1) 4) •••
SP4 17Check air cleaner 1) •
SP417Change air cleaner 1) •
SP5 17 Check V-belt tension 1)
•
SP6 17 Check valve clearance 1) 2) •
FUEL SYSTEM:
SP7 18 Check primary lter (Racor) 2) 3) •
SP8 18 Change primary lter element 2) 3) •
SP918 Change secondary fuel lter 1) 3) •
SP12 20 Check injectors 1) 3) 5) •
SP13 20 Check fuel injection pump 6) •
COOLING SYSTEM:
SP10 19 Check cooling water level •
SP11 19 Check and ush cooling system •
SP14 22 Check and clean heat exchanger •
SP15 22 Change impeller in raw water pump 1) 3) •
SP16 22 Check exhaust elbow •
ELECTRICAL SYSTEM:
SP17 23 Check electrolyte level in batteries 1) •
SP18 23 Check condition of batteries 1) •
OUT OF SERVICE:
SP19 23 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
SP7 Checkprimaryfuellter
SP10 Checkcoolingwaterlevel
AFTER FIRST 50 HOURS:
SP2/3 Changeengineoilandlter
AFTER FIRST 100 HOURS:
SP2/3 Changeengineoilandlter
EVERY 100 HOURS:
SP6 Checkv-belttension
SP17 Checkelectrolytelevelinbatteries
EVERY 200 HOURS:
SP2/3 Changeengineoilandlter
SP4 Checkaircleaner
SP18 Checkconditionofbatteries
EVERY 500 HOURS:
SP8 Changeprimaryfuellterelement
SP9 Changesecondaryfuellter
SP15 Changeimpellerinrawwaterpump
SP16 Checkexhaustelbow
EVERY 1000 HOURS:
SP5 Changeaircleanerelement
SP12 Checkinjectors
EVERY 2500 HOURS:
SP13 Checkfuelinjectionpump
SP11 Checkandushcoolingsystem
SP14 Checkandcleanheatexchanger
1) Perform all maintenance every two years at minimum, even if hour level has
not been reached.
2) Consult manufacturer's maintenance schedule, note on chart.
3) Whenever necessary.
4) After rst 50 hours, then at 100 hours, then every 200 hours.
5) Clean injection nozzles every 1500 hours.
6) 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.

OM773LW3 11/20
16
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CJ/CK15-40singleviscosityoils.
 b.APIServiceCJ/CK15-40multi-viscosityoils.
3. Usetheproperweightoilforyouraverageoperation
temperature.
Figure 7: 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.
SP-1. CHECKING OIL LEVEL
1. Checktheoillevelinthecrankcasewiththedipstick.
Theoillevelmustbeinthewaedarea
 onthestick.Neverallowtheleveltogobelowthis
area.Followthelubricationrecommendationsabove.
SP-2. 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diesel-ratedbreakinoil(JohnDeere
pre-packagedorequivalent)duringtherst100hours.
Consultyourdealerformoreinformation.
2. Changetheoilandlteragainat100hoursusingthe
oilrecommendedinFigure7.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:
M773LW3(G) - 4.75 quarts (4.9 liters)
SP-3. CHANGING LUBE OIL FILTER
1. Changethelubeoillterwitheveryoilchange.
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mountingsurface.
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element.
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. Oillterpartnumbersare:
M773LW3(G) - #24-02002
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 11-2-20

OM773LW3 11/20
17
SP-4. AIR CLEANER
1. Inspectaircleanerevery200hours.Industycondi-
tions,checkmoreoften.
2. Ifdirty,washelementinsoapywater.Rinseanddry
thoroughlybeforere-installing.
 Replaceifnecessary.Partnumbersare:
M773LW3 – #24-28602
NOTE: Failure to change air cleaner at recommended
times can cause severe engine damage. Change
every 1000 hours or two years, whichever comes
rst.
NOTE: Make absolutely sure no impurities enter the
engine while changing the element. Do NOT run the
engine with the air cleaner removed.
SP-5. 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 8: Valve Adjustment
SP-6. VALVE CLEARANCES
1. Adjustvalveclearanceafter1000hoursorasneeded.
2. TobringtheNo.1cylindertotopdeadcenterinthe
compressionstroke,alignthetimingmark;thetop
markofthecrankpulleywiththatofthetiminggear
case.Removetherockerarmcoverandturnthe
crankshaftfowardandbackward.Iftheinletand
exhaustvalvesoftheNo.1cylinderdonotmoveitis
intopdeadcenterposition.Whenthevalvesmove,
orrock,turnthecrankshaftonefullturnandalignthe
topmarkofthecrankpulleywiththetopmarkofthe
timinggearcase.
3. 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 10).
Clearanceonbothintakeandexhaustvalvesshouldbe
0.008in.(0.2mm).
4. Repeatsteps3and4foreachcylinder.Eachsetof
valvesmustbeadjustedindividually.
5. Replacetherockerarmcover.Tightencovernutsto
5-8ft/lbs(0.8-2.3kg/m).
Figure 9: Timing Mark
Cylinder No. 1 2 3
Valve Arrangement Int. Exh. Int. Exh. Int. Exh.
When No.1 cylinder
is at Top Dead Center
in the compression
stroke
With the crankshaft
turned 3600in
normal direction from
above
Valve Arrangement
Updated 8-14-19

OM773LW3 11/20
18
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.
2. Uselowsulphurorultralowsulphurfuel.
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.
FUEL FILTERS
1. Yourgeneratorsetshouldhaveaprimaryfuellter
installed.WerecommendtheRacorbrandoffuel
lter-waterseparators.
SP-7. PRIMARY FUEL FILTER
 a. Checktheprimaryfuellterdailyas
  recommendedbytheltermanufacturer.
  Emptythecollectionbowlasnecessary.
SP-8. PRIMARY FUEL FILTER ELEMENT
 b. Changetheelementasoftenasnecessaryor
  every500hours.
 c. Ifthebowlllswithwater,changetheprimary
  andsecondaryelementimmediately.
SP-9. SECONDARY FUEL FILTER
2. Changesecondaryfuellterevery500hoursoras
necessary.
 a. Removethespin-onlterbyturningit
  counterclockwisewithalterwrench.Fillthe
  newelement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. Fuellterpartnumberis:
M773LW3(G): #24-52020
Updated 10-19-20