Onan MDJF Series Instruction Manual

OPERATORS
AND
ANUAL
FOR
Onan
ELECTRIC GENERATING SETS
MDJF
SEkiES
t
968-0345
6Abt3

TABLE OF CONTENTS
TITLEPAGE
GeneralInformation 3
Specifications 4
Dimensions and Clearances 5
AssemblyTorques and SpecialTools 7
Installation 8
Operation . 17
Adjustments 21
GeneralMaintenance 24
RoutineCheckChart 26
MaintenanceSchedule . . 27
TroubleshootingGuide 28
PartsCatalog 29
PERFORMANCE
CERTIFIED
We certify thatwhenproperlyinstalledand operated
thisOnanelectricplant will deliverthe full powerandthe
voltageandfrequencyregulationpromisedbyits nameplate
andpublishedspecifications.Thisplanthas undergone several
hours ofrunning-inandtesting under realisticloadconditions,
in accordance with procedures certified byanindependent
testinglaboratory.
ONAN 140073RDAVENUE
N.E.• MINNEAPOLIS,MINNESOTA55432
*OIVISIOH Of ONAN CORPOI'llON
IMPORTANT! RETURN WARRANTY CARD ATTACHED TO UNIT.

INTRODUCTION
THISOPERATOR'S MANUAL CONTAINS INFORMATION PERTAINING
TOTHEINSTALLATION,OPERATION,ANDMAINTENANCEOFYOUR
ONAN UNIT. A PARTSCATALOGISALSOINCLUDEDINTHIS
MANUAL.
WESUGGESTTHATTHIS MANUAL ANDTHE WIRING DIAGRAM WHICH
ACCOMPANIES EVERY ONAN UNIT BERETAINEDAND REFERRED
TO WHEN MAKING EQUIPMENTADJUSTMENTSORORDERINGPARTS.
ADDITIONALCOPIESAREAVAILABLEFORA NOMINAL CHARGE
FROMYOUR ONAN DISTRIBUTOR.
WHEN ORDERINGPARTSREMEMBERTOINCLUDETHE ONAN
MODEL,SPECIFICATION LETTER, ANDSERIALNUMBERLOCATED
ONTHENAMEPLATEOFYOUR ONAN UNIT. THISISESSENTIALTO
ENSURE THECORRECTPARTISSHIPPEDTOYOU.
FOR MAJORREPAIR SERVICE, CONTACTYOUR ONAN AUTHORIZED
DISTRIBUTOR.

GENERAL INFORMATION
When theinsttuctionsinthismanualrefertoa specific
modelofgeneratingset,identifythemodelbyreferring
tothe MODEL AND SPECIFICATION NO.asshownon
the Onan nameplate. Electrical characteristicsareshown
onthelowerportionofthesetnameplate.
How to Interpret MODEL and SPEC NO.
15 OMDJ F - 4R/ 96 D
1 3
4
1.Factory code forgeneralidentification.
2. Specific Type:
E - ELECTRIC. Electric startingatthesetonly.
R - REMOTE. Electric starting.Forpermanentinstalla-
tion,canbeconnectedtooptionalaccessoryequipment
forremoteorautomaticcontrolofstartingandstopping.
3. Factory code foroptionalequipment.
4.Specification(Spec)letter(advanceswhenfactory
makesproductionmodifications).
CAUTION
'Onan uses this symbol throughout the text
to warn ol possible equipment damage.
WARNING |^"ssym^'s used to warn ol any possi-
H^HHMBBi^J&/e personal injury.
MANUFACTURER'S WARRANTY
Onanwarrants.Inihe nrigmal iiAt-r. thaitar.bproductofitnma mi fact u
is frrr frnm drfwlft in. motrriol onH fnrlory workmanshipifproperlyin*
siollcil. servicedandoperatedundernormalconditionsaccordingto Onan's
inplrnrlinno.
Onan will, underthis worrnnty. repairnrreplace,asOnanmayelect,any
pan which onexamination nhall diocloaeto Onan's fintisfaction lohove
hern defeciiveinmaterialandworkmanship:providedlhatsuchpart .ihall
hereturnedto Onan's factoryoroneofitsAuthorizedServiceSta linns,
ironsporluiion charges prepaid,not hiler thanone f I) yearaflertheproduci
if first placedin wrvic*. Suchdefectivepart will herepairedorreplaced
freeofcharpe, including lahor(in accordance wilh rates approvedhyOnon)
during ihestatedone(1)yearcoverageunder thin warranly.
THIS WARRANTY AM) ON.AN'S OII LIGATION TMKRF.l'NDK.H IS
IN l.l KL.' OKALL VIARK.ANTIK.S. KX I'H KSSK.I) OK I.MPUKO. IN-
<XUr>l.N(; WITHOUT LIMITATION.THK IMIMJKI) W.ARRANTIKS
OK MKRCIIANTAIIIUTY AND K ITN KSS KOHA PARTICULAR
I'l HI'O.SK. ANOAM. OTIIKH OIII.I<;ATIONS OR I.1ABILITIKS.
I.NCI.I IHN<; LIAHILITY KOK INCIDKNTAI. AND CONSKQt'KN-
TIM. DAM ACK.
No ]MTMin i>aulhoriiedlopi\eanyotherwarrantyorloa*<iumeany olhei
lialiililt on Onan's (..-half unh-** made ora KM u med' in wrilinp hyan fKhr.
of * Inuu. amino jiernon ii> uulhorizediopiveanvwarranlvoi
liuhililies ..niheSeller's l.ehalf unle« made'ora^nmedin writinp hy
>urh Sell. r.
ONAN

SPECIFICATIONS
Nominal dimensionsofgeneratingset(inches):
Height 2611/16
Width 205/16
Length '.513/8:'
Weight (approx.lb.)'. :.'..".....865
Numbercylinder(vertical in-line) 4
Displacement(cubicinch)140
Cylinder bore< , 31/2
Pistonstroke3 5/8
BHP at1800rpm: 33.3
RPM (for 60 hertz) 1800
RPM (for50hertz)1500
Compressionratio19:1
Battery voltage(ACset,exceptdualpurpose)*12
Batery size (ACset,exceptdualpurpose)
SAE group IH-two in series • Yes
Amp - hr,SAE20- hr(nominal)120
Battery charge rate amperes (normal)- AC sets 2 to5
*Oil capacityinU.S. quarts - Refill : .•6
Cooling water flow (gallonsperminute). ' 6
Generatorcoolingair (CFM at1800rpm)136
Combustion air (CFM at1800rpm): ^ '2
Total cu.ft.permin.ofairrequired208
Diesel fuel lift (maximumfeet).'6 •"
Maximum recommendedpower take-off from front pulleyatanyload2 hp
Power take-off limit atratedload'. 1 hp.
Injection pump (Am. Boschtype)PSU
Output isratedat unity powerfactorload 1-phase
Output isratedat0.8powerfactor 3-phase
Rating (outputinwatts)
AC, 50hertzset.,12,000
AC, 60hertzset, 15,M0
AC voltageregulation in t %
: ; 3
AC frequencyregulationin % .•5
Revolving field type generator , Yes
120/240- volt single phase modelreconnectibleYes
Statictypeexciter(Magneciter): Yes
* - Plus1/2quartfornew filter.
• . 24and32voltbatteriesoncertainmodifications.
NOTE: Hertzisa unit offrequencyequaltoonecycleper second.

DIMENSIONS AND CLEARANCES
Allclearancesgiven at roomtemperature of 70°F.
Alldimensions in inchesunlessotherwisespecified.
MinimumMaximum
CAMSHAFT
Bearing JournalDiameter,Front2.25002.2505
Bearing Journal Diameter, Rear 1.1875 1.1880
Bearing Clearance Limit 0012.0037'
End Play,Camshaft(inback position) 007.039
Cam Tappet Hole Diameter8755.8765
Cam TappetDiameter8730.8725
CONNECTINGRODS
Large BearingDiameter (I.D.) ' 2.06152.0630
Small BushingDiameter (I.D.) . . . 0.99030.9906
Clearance,LargeBearingtoCrankshaft' 001.0033
CYLINDER
Cylinder Bore3-1/2
Cylinder Diameter Limits 3.49953.5005
CRANKSHAFT
Main BearingJournalDiameter2.24272.2435
Crankshaft Main BearingClearance (Original Equipment)0030.0043
Connecting RodJournalDiameter2.05972.0605
End Play,Crankshaft010.015
PISTON(Measure 90°toPin)
Piston Clearanceto Cylinder Wall belowOil Ring Groove0055.0075
Piston Pin Hole Diameter99005.99025
Ring Groove Width, Top097.098
Ring Groove Width, 2nd. .0965.0975
Ring Groove Width, 3rd0965.0975
Ring Groove Width, 4th1895.1880
PISTON PIN
Length 3.003 2.988
Diameter 9899.9901
Piston ClearanceThumbPushFit
Connecting RodBushingClearance0002.0007
PISTON RINGS
Ring Type
Top Compression
2nd Compression
3rd OilScraper& Compression
RingWidth
Top f 0925.0935
2nd 0925.0935
3vd *":::09251 .0935

Minimum Maximum
STARTING MOTOR
Rotation ". . . . Counterclockwise
Pinion Clearanceto Pinion Stop(SolenoidPlungerBottomed).070.120
Pinion RestPosition — Distance from Pinion Housing Mounting Face
to OuterEdgeof Pinion 1-9/32 1-15/32
Armature EndPlay.005.030
TestSpecifications
No Loadv.;10volts- 80 amps
5000 rpm Min.
Stall Torque4volts- 420 amps
7.8lbs. ft. Min.
Brush SpringTension32-40 ounces
with new brushes
VALVE, INTAKE (Hardened Chrome Alloy)
StemDiameter.3405.3410
ClearanceinGuide'. . . . . . .0015.0030
Valve Face Seat Angle . . . 426
Valve Clearance.017
VALVE, EXHAUST (Hardened Chrome Alloy)
StemDiameter3405.3415
ClearanceinGuide". . . .0030.0050
Valve Face Seat Angle 45°
Valve Clearance.017

ASSEMBLY TORQUES AND SPECIAL TOOLS
TORQUE SPECIFICATIONS FT.-LB.
Center Main Bolt 97-102
Connecting Rod Bolt 27-29
Cover-RockerBox8-10
Cylinder Head Bolt 44-46
Exhaust Manifold Nuts13-15•
Flywheel Mounting Screw65-70
Flywheel HubNut17-21
Fuel Pump Mounting Screws. 15-20
Gear Case Cover. 18-20
Glow Plug10-15
Injection Nozzle Mounting Screws20-21
Injection Pump Mounting Screws15-16
Intake Manifold 13-15
Oil Base Mounting Screws45-50
Oil Filter Hand Tight + 1/4to1/2 Turn
Oil Pump Mounting Screws15-20
RearBearingPlate4045
Rocker Arm Nut4-10*
Rocker Arm Stud. ...35-40
Thru-Rotor-Stud Nut55-60
* - Thistorqueis friction betweenthe threads only and
locks thenutsinplace.Therockerarmnutsarefor
adjusting valvelash.
CAUTION
Tighten nuts evenly to avoid manilold
damage.
Assembly torques assure propertightness without dangerof
stripping threads.Ifa torquewrenchisnotavailable,
estimatethe degree oftightness.Use reasonable forceand
awrenchofnormallength.
SpecialPlaceBoltsdonotrequirelockwashersor gaskets.
Never attempttousea lockwasher with these bolts,it
will defecttheirpurpose.Checkallstuds,nutsandscrews
often. Tightenasneeded.
SPECIAL TOOLSANDEQUIPMENT
These toolsareavailable from Onantoaidserviceand
repair work.
CrankshaftGear Pulling Ring 420-0275
Diesel CompressionTester420-0283
Diesel NozzleTester420-0184
Diesel PintleNozzleCleaning Tool Set
(Includes injection nozzlecentering tool) . . . 420-0208
Driver, FrontCamshaftBearing420-0252
Driver, RearCamshaftBearing420-0251
Driver, CenterCamshaftBearing420-0254
Driver, Main BearingFrontandRear420-0269
Driver, Valve Seat 420-0270
Oil SealGuideand Driver RearFront420-0281
Ridge Reamer420-0260
ReplacementBladefor420-0260420-0261
Valve Seat Remover420-0272
ReplacementBladesfor420-0272 4 20-0274

INSTALLATION
GENERAL
Proper installation is very important. Consider thefollowing
points: adequate generator coolingair; discharge ofcircu-
lated air; adequate fresh inductionair; adequate engine
cooling water; discharge of circulated water; discharge of
exhaust gases; electrical connections; fuel connection;
sturdy andflatfloor;and accessible for operation and
service. Use this manual asa guide to help withthe
installation; refer toTypical Installation, Figures 2 and3.
For more complete instructions, request Onan Technical
BulletinT-021.
Each installation must be considered individuallyand exe-
cuted in compliance withall regulations whichmay affect
the installation. The advice and guidance contained inthe
booklet entitled Fire Protection Standard (orMotor Cralt:
(NFPANo.302) offered bythe National Fire Protection
Association International, Boston 10, Massachusetts, will
behelpfultothe installer of equipment in vessels.
CAPSCREW
LOCKWASHER
FLATWASHER
SNUBBER
"GENERATOROR
OILBASEMOUNT-
INGFOOT
CUSHION
MOUNTINGSPACER
BUSHING
'-DRIPPAN
FIGUREI.MOUNTINGCUSHION
LOCATION
Select a location fortheunit, preferably near the vessels
main keel, whichisdry, properly ventilated, above low
lying vapors and splash fromthebilge. Provide accessibility
for minor servicing operations, draining ofthe crankcase,
lubricatingoilandthecooling system.
MOUNTING
Thefloor should beflatand give support directly under the
set (Figure 1) mounting points. Theunit will rock onits
mounts.
A 2-1/2inch clearance around theunitis required to permit
rockingonits mounts without restraint. Use adequately
flexible exhaust line,fuelline, batteiy cables, and elec-
trical wires.
WATERLINE EXHAUSTHIGHWATERTEMP-
ERATURECUTOFFSWITCH
SUPPORT
MUFFLER
RUBBER
EXHAUST
HOSE
.^LOAD
<LWATER
LINE
VENTILATED
BATTERYBOX
FIGURE2.TYPICALINSTALLATION

Recommendedfluahtypethru-hull
fittingandwaterfilter.
TOGENERATORSET
SEACOCK
STRAINER
v— FLUSHTHRU-HULL
FITTING
WARNING:Donotusescooptypewaterinletfittings
ongeneratorsetsusingAqualiftmufflersystems
CAUTION Install Siphon Break Kit #155-0950 il
exhaust injection elbow is below load
wa'er line. Locate the Siphon Break at least 12inches
above load water line and in a vertical position. Remote
mounting the siphon break is permissible within a 5 loot
radius ol water injection exhaust elbow. Vertical position
and height ol valve must be maintained.
SIPHONBREAK•
(Seedetail)
-HANSERSTRAPS
Sf|VACUUMRELIEFVALVE
ADAPTER
/""ELBOW(2)
'RUBBERHOSE
WATEROUTLET
EXHAUSTWATER
INJECTIONELBOW
EXHAUSTOUTLET
TYPICAL ABOVE WATER LINE
INSTALLATION
NOTE:
Makeprovisionforpassageofairbeneath
mufflertopreventcondensation..
TYPICAL
BELOW WATER LINE
INSTALLATION
FIGURE 3. TYPICAL INSTALLATION
Installtwo hold-down clamps tothedrippan(frontand rear
or both sides). Secure the clamps tothe mounting base. For
maximum noise reduction on Onan MDJF units, installthe
Onan "Sound Shield" whichisan insulated fiberglass
enclosure which completely surrounds'the generating set
(Figure 2). Openings are provided for connection toallex-
ternal lines and wires. Internal air ducts reduce air borne
noise toa minimum. Contact your localONAN dealer for
noise reduction methods andthe special kits whichare
available.
shut-off valve atthe tank. When thefuel tank is shared with
another engine, usea separate fuellineand return linefor
each to avoid starving the plant. (Figure 4)..
If fuel lift must exceed 6-feet, installanauxiliary electric
fuel pump atthefuel supply.
FUEL TANK
If a separate fuel tank is used, installthe tank sothe bottom
is less than 6^feet below thefuel pump. The tank top must
be below fuel pump levelto prevent siphoning. Installa
FUEL CONNECTION
Connect the fuel line to the fuel pump inlet. Pump is threaded
7/16-24 NPTF (American Standard Internal Tapered Pipe
Thread). Important: Always use llexible tubing between en-
gine and the luel supply.

Thedieselenginerequiresa fuel supply line anda separate
fuel return line. Install the fuel return line from the7/T6-24
sizeopeninginthe overflow fitting locatedonthe injection
pump(wherethenozzle fuel return line isalsoconnected)to
thetopofthe fuel supplytank(Fig.5).
Do notusegalvanizedlines, fittings, or fuel tanksinthe
fuel system.Carefullycleanall fuel systemcomponents
beforeputtingtheplantintooperation.Any dirt orcontam-
ination may cause major damage tothe fuei injection system.
OIL DRAIN
Theoildrainmaybeextendedtosuittheinstallation.The
oil base hasa 1/2"pipetappedhole.
^SHUT
FUEL
TANK
BELOW FUEL
— FUEL PUMP LEVEL
RETURN
LINE
PROPULSION
ENGINE
• FUEL
RETURN
LINE
GENcKATOR'
FIGURE 4. FUEL LINE ARRANGEMENT
VENTILATION
Thegeneratingsetrequiresfreshairforcombustionand
generator cooling. Onanrecommendsthattheventilation
systembeabletodeliver1-1/2to2 timestheairrequired
b; theset.Whentheventilationsystem depends on wind
or boatmotion,usepowered exhausters toprovideventila-
tion whentheboatisnotinmotion.Formore information,
refertoOnanTechnical Bulletin T-021.
EXHAUST
WARNING
^Pfpe exhaust gases outside of the hull
I - exhaust gases are poisonous!
SeeInstallation,Figures2 and3.Theengineexhaust
connectionis 1-1/2" pipetapped.
Install a separate exhaust line as follows:
1. Abovevesselloadwater line.
2. Pitcheddownwardtopreventwaterbackflow.
3.Shield line near combustiblematerial.
4. Use flexible hose ortubing.
5.Forturnsusesweeping (long radius)elbows.
6. Increase onepipesizeforevery10ft.inlength.
CONNECT
FUEL RETURN
LINE HERE
(Flexible Line)
RETURN
LINE
Providea teeforwater line connectionforwetex-
haust (Figure3)- refertoWaterDischarge Line
Instructions. Raise thedryportionoftheexhaust
line high enoughtopreventwaterbackflowinginto
theengineunderallconditions.
Thewaterjacketedexhaust manifold ispipetapped
atboth ends forconvenienceinexhaust line conn-
ection.
FIGURE 5. FUELSYSTEM
AQUALIFT MUFFLER (Optional)
The Aqualift isa highly efficient marine muffler designedfor
aboveorbelowwater line installationswhenwatercooled
exhaust systems areused. Because ofinstallationvariables,
customersmustprovidethebrackets, hoses andclamps,re-
quired forinstallation.
10

IMPORTANT: DO HOT USE SCOOP TYPE WATER INLET
FITTINGS when installing an Aqualilt mulller. Forward lacing
scoops develop sullicient ram pressure to lorce water past
the set's water pump, Hooding the exhaust system where it
may (low back, Hooding the engine cylinders. This can
happen only il the electric set is not running and boat is
underway.
1. Secure themufflertothe predetermined location (within
ten-feet ofthe engine exhaust outlet) using "L"
brackets (Figure 6)or other suitable mounting devices
such aswood blocks or metal straps. Flexible mounts
maybe used ifso desired. Allow forair passage under
mufflerto prevent condensation.
OUTLET
NOTTO
EXCEED
1INCH•
•L" BRACKET
(MINIMUM
OF3)
<j£iLOCKWASHER
jg*- NUTBASE
SHORTNIPPLE
DOUBLETAPPED
TANKBUSHING
LONG NIPPLE -p
,(INSIDEV .
MUFFLER)
r
SHORT
NIPPLE
REDUCERPIPE
BUSHING
NOTE:LONGNIPPLEGOESINSIDETANK
FIGURE6.SECURINGTHEMUFFLER
FIGURE7.AQUALIFTMUFFLER
3.. Connect the exhaust linetothemuffler outlet andtothe
upper elbow. A conventional automobile tail-pipe hanger
bracket maybe used to hang the upper elbow. Rigid pipe
maybe used in place offlexible hose for certain applica-
tions. There must bea pitchof one-half inchperfoot
(i.e.,a 2-1/2" drop fora 5'run)inthe exhaust tubing
between the engine exhaust elbow andthemufflerinlet.
Muffler maybe mounted below thelevelofthe engine if
necessary. A minimum drop of one-foot is necessary be-
tween the engine exhaust outlet onthehullto prevent
water from washing intothe system (seeFig.3).Anin-
crease ofone standard pipe size for every ten running
feet of exhaust fromthemufflertothe exhaust outlet is
necessary to prevent excessive backpressure.
pT^Cjrr^Donot drill holes higher than oneinch
LA55-A-PAA^ X above the extreme lower edge ofthe
muffler when installing mounts.
4. Connect the exhaust linefromthe upper elbow totheex-
haust outlet onthe hull. The exhaust outlet onthehull
must be positioned so that a minimumot water will enter-
whileat anchor or under way.
Important: Be sure all liftings are tight.
2. Connect the exhaust line(l1/2")tothe marine elbow on
the engine andtothe exhaust inletonthemuffler.The dis-
tance fromthe base oftHemufflertothe upper elbow on
the exhaust tubing fromthemuffler outlet must not exceed
four-feet (see Figure 3). L^j^^^x^^^i interior
the lile expectancy;
on the mulller will damage the
protective coating decreasing
11

WIRE
SIZE
DISTANCE
#18 to
65ft.
#16 to
100ft.
#14 to
150 ft.
#12 to
280ft.
FORWARD
SLEEPINGQUARTERS
PILOT'S
STATION
GENERATOR
MOMENTARYCONTACT
SWITCH
(Onan No. 308-0155 or equal)
FRONT
DRAINBLOCKHERE PRIMING
PLUG
7REMOVEPUMPCOVER
TODRAIN
RUBBERHOSE
(LINEFROMWATER
SOURCE) 1/2"I.D.
OR LARGER ~~
LOOSENLINE
TODRAIN
EXHAUST
MANIFOLD
DRAIN
HERE
STARTING
MOTOR
BATTERY
NEGATIVE:
6VOLT
BATTERIES «»
FIGURE 8. FILL AND DRAINLOCATIONS 12
FIGURE 9. REMOTECONTROLSAND BATTERY
CONNECTIONS

BATTERY CONNECTION
Battery requiresnegativeground.Donotattemptto change
batteiy polarity on these sets. Refertoset wiring diagram.
CAUTION
11 the battery is connected to the charging
circuit with the wrong polarity, damage
will occur alter three minutes while stopped or in live
seconds while running. Alternator windings will be damag-
ed almost instantly il battery charging circuit is shorted
belore the resistor.
Refertosetnameplateforbatteryvoltage.ForAC
plants with 12 volt system,providetwo6 volt batteries
connectedin series (onebattery'snegativetotheother
battery'spositive,Figure9)for105amp-hr,12 volt source.
For ACplants with 32 volt system,provide32 volt setof
batteriesand200amperefused switch, see wiring diagram
for connections.
Connectthebatterypositive(+)tothestarterengaging
solenoid terminalpost.Connectthefcattery nega-
tive (-) toa goodgroundontheengine.(Figure9).
WATER SUPPLY LINE (FIGURE 8)
A continuoussupplyof cooling waterisrequired.The
waterpump inlet is1/4"pipethreadto1/2" hose coupling.
Usea sectionof flexible hose near thesettoabsorb
vibrations. Theinsidediameteroftheplumbingmustbe
1/2"orlarger.Usepermatexorotherpipe sealer onall
pipe fittings insupply line topump. Normally, thepump
should deliver6 gallonsof cooling waterperminute.
Measurethedischargedwater flow afterthermostatopens,
to assure thesupply line islargeenough.Reduceresistance
on piperunslongerthan5-ft.byusinglargerinsidedia-
meter plumbing. Toprovesuction line isair tight, seethat
nobubbles appear indischargedwater.Anairleak reduces
lubrication andshortens life ofpumpsimpeller. Install a
strainerinthewatersuction line inlet andwhereaccessible
for cleaning.
REMOTE START - STOP SWITCH (OPTIONAL)
For remote control startingandstopping,use3 wiresto
connecttheremote switch (SPDT,momentarycontact,center-
off type)totheterminalblockmarkedB+,1,2,3,inthe
set control boxusing wire sizes as listed inFigure9.Pre-
heat circuit requiresanextra wire toterminalH and
momentarycontact switch (SPST)connection.Remove
jumper betweenterminals3 andH before installing remote
wiring.
LOAD WIRE CONNECTIONS (AC)
Thesetnameplateshowstheelectricaloutputratingofthe
setinwatts,voltsandhertz.Theset wiring diagramshows
theelectricalcircuitsandconnections necessary forthe
for theavailableoutputvoltage. Also seeFigure12.
Meet allapplicableelectricalcoderequirements. Work
should bedonebya qualified servicemanorelectrician
because theinstallation will beinspectedandapproved.
Theset control box (junction box)hasknockoutsections
to accommodateloadwires.Use flexible conduitand
strandedloadwires near thesettoabsorb vibration. Use
sufficiently largeinsulatedwires.Stripinsulation from
wire ends as necessary forcleanconnections.Connect
eachload wire tothepropergeneratoroutput,leadinside
theset control box.Insulate bare ends ofungrounded
wires. Usea bolt (throughthe control box)toconnect
thegrounded(-i-)generatorleadandload wire. Install
afusedmain switch (or circuit breaker)betweenthegen-
erating setandload(Figure11).Ifa testrunindicates
wrong rotationof3 phase motorsintheload circuit, switch
theconnectionsatanytwogeneratorterminals.
Balance . All Loads:Cunentforanyoneoutputloadmust
not exceednameplate rating. Overloadingcan damage
thegeneratorwindings. Divide theloadsequallybetween
output leads.
Single Phase Loads on Three Phase Generators: Any
combination ofsingle phase andthree phase loadingcan
beusedatthe same timeas long asthecurrentforany
oneoutputlead does notexceedthegeneratornameplate
rating.
TOLOAD
GENERATOR
120-V.
FUSE OR CIRCUIT
BREAKER
GROUNDED CURRENT CARRYING CONDUCTOR
UNGROUNDED CURRENT CARRYING CONDUCTOR
THESE LINES FROM ^
DOCKSIDE POWER SOURCE
FIGURE II. DOCKSIDE POWERSOURCE
13

Output LeadMarkings:GeneratorsaremarkedTl,T2,etc.
These identifying marksalso appear onthe wiring diagram.
Voltage SelectiononReconnectibleSingle Phase Genera-
tors: These modelsarereconnectibleforuseasa 120/240
volt 3 wire; a 120 volt 2 wire or240volt2 wire powersource
(Figure 12).
Load Connections:Refertothe figure which illustrates
theloadconnectionsfortheoutputshownonyour set's
nameplate.
CAUTION Do
not use existing neoprene impeller
water pump lor hot water side ol cooling
system. Heat or soluble oil (in many rust inhibitors and
anti-lreezes) will damage the impeller. Always connect
the neoprene impeller pump to the cold water side. Use
acentrifugal metal impeller water pump (Onan #132-0110
or equal) in the hot water side. Drive it with a belt from
the set's power take-oll.
Spec A throughC:Useanexpansiontankinthehotwater
side.
Delta Generator:GeneratorleadToisthegeneratorcenter
tapbetweenTlandT2.TheToleadisnormallynot
groundedbutcanbegroundedifrequired(Figure 12-B).
Single phase poweratcentertappedlegavailableupto
2/3of full ratedthree phase power.
Discharged water leaves at heat exchangerandthento
exhaustsystemwater inlet. Supply line connectionsare
the same asstandardsystem(Figure13).Refertothe
instructions forwatersupply line inthissection.
Fill closed cooling systems with clean,alkali-freewater,
to theproper level. Addanapprovedrust inhibitor tothe
coolant. Ifthecoolantisanti-freeze,testitperiodically.
HEAT EXCHANGER COOLING (Optional).
This isa closed cooling systemcommonlyreferredtoas
fresh water cooling. Watercirculatedthroughtheengineis
termed fresh. water,hotwater,jacketedwater,etc.Water
circulated throughthe heat exchanger only iscalledraw
water,seawater, cold water,dischargedwater,etc.This
system (with anti-freezecoolant)isrecommendedwhere
freezing hazards existorwheretheownerwantstoprevent
saltwaterproblems.
Two conditions prevail: (1)Factoiyinstalled heat exchanger,
and(2)CustomerinstalledOnan heat exchangerkit.Get
details from Onan.
Install a newzinc "pencil" (Figure13) which screws into
fresh wateroutletendof heat exchanger,everytwomonths
or asinspectiondictates.
l^^y^QlJ^jj Use high temperature cut-oil switch in
overheating.
1 the hot water side to protect unit Irom
14

UNGROUNDEDLOAD
WIRE(BLACK) -Q
Tl-T3oe
120 V.
(JOIN) o
<Q
ae<
GROUNDEDLOAD j-^
WIRE (WHITE)_JC~""^
T2-
T4
LU
O
UNGROUNDEDLOAD
WIRE(BLACK)
T OT..T4.?<
2s
] GROUNDEDLOAD
.WIRE(WHITE)
(JOIN)
T2
—(JOIN AND GROUND)
UNGROUNDEDLOADWIRE(BLACK) o
120 V.
240 V.—J
120 V.
GROUNDEDLOADWIRE(WHITE)
UNGROUNDEDLOADWIRE(BLACK)
IPhase,ReconnectibleGenerator
(60hertz1model has code -3C gives 2 wire or3 wireservice)
o
Tl O
t- u>
2
<Q
- «<
O "JUi
-i Z—'
ui
T4 O
3 PHASE
NAMEPLATE
(HIGHER
x
VOLTAGE)
UNGROUNDEDLOADWIRE(BLACK)
UNGROUNDEDLOADWIRE(BLACK) o
k^UNGROUNDEDLOADWIRE(BLACK)^
rn u
AAA
j , rGROUNDEDLOADWIRE(WHITE)
A= N ameplatelowervoltage,!phasecireuit
B = Namepiate highervoltage ,1 phasecircuit
(60hertz 120/208 voltmodelhascode -4)
Y—Connected
2
Tl
4/1
Q
<
O
T3 <
oe
LU
TO 5
3 PHASE
NAMEPLATE
(HIGHER
VOLTAGE)
NEUTRAL LOADWIRENORMALLYUNGROUNDED ^
T T TOISTHE GENERATOR S CENTER TAPOT0
A A BETWEEN TlANDT2
UNGROUNDEDLOADWIRE(BLACK)
UNGROUNDEDLOADWIRE(BLACK)
UNGROUNDEDLOADWIRE(BLACK)
A =N a m epl at e lowervo 11 age,l p h as e circuit
B = Nameplate higher voltage,1 phasecircuit
DeltaConnected(60hertz120/240voltmodel has code -5D)
SINGLE PHASE POWERAT CENTER TAPPED
LEG AVAILABLE UPTO2/3OF FULL
RATED THREE PHASE POWER
to
Q
<
On
-OT2
•O73
O
•—
<
ee
Ui
Z
Ui
o
FIGURE 12. WIRINGCONNECTIONS
15

OUTLET-
RAWWATER
TO
EXHAUSTLINE
REARCYLINDER
BLOCKCONNECTION
,ENGINEDRIVEN
WATERPUMP
(RAWWATER)
RAWCOOLINGWATER
FROMSOURCE
SPECIFICATION A THROUGHC
FRONTCYLINDER
BLOCKCONNECTION
CENTRIFUGALPUMP
(FRESHWATER)
RAWWATER
^FRESHWATERINCLOSEDSYSTEM
THERMOSTAT
HOUSIN FILL -BLEEDERVALVE
WATERMANIFOLD HEAT
EXCHANGER
ENGINEDRIVEN
WATERPUMP
(RAWWATER)
RAWWATER
DISCHARGE
REARCYLINDER
BLOCKCONNECTION
—•—•-—--~RAWWATER
""FRONTCYLINDER
BLOCKCONNECTION'WWFRESHWATERINCLOSEDSYSTEM
INLET- RAWWATER
CENTRIFUGALPUMP
(FRESHWATER)
BEGINSPECIFICATION D -HEATEXCHANGER•
BRACKET
FIGURE 13. HEATEXCHANGER PLUMBING
16

OPERATION
CRANKCASE OIL
Useanoil with theAPIdesignationCD/SE,orCD/SD
(formerly DS)thathas passed the Series 3 Testandat
least Sequences IIAandHIAoftheAutomotiveManu-
facturer'sMS Sequence Tests.(DMoil which has passed
theAutomotiveManufacturer'sMS Sequence Tests andthe
MIL-L-2104B Tests mayalsobeusedwhenambienttempera-
turesarelowerthan 30°F.) Toreduceoilconsumption
to a normal level intheshortesttimeona neworrebuilt
"J" series dieselengine,useCC (formerly DM)oil (pass-
ing theMS Sequence Tests)forthe first fill only (50to100
hours),then change totherecommendedoil.
TEMPERATURE
Above 32
0F
0oFto320F
Below 0oF
GRADE
SAE 30
SAE .10W-30,5W-20,or
10W, 5W-30
SAE 5W-20or5W-30
Do notmix brands or grades. RefertoMaintenanceSection
for recommendedoil changes.
RECOMMENDED FUEL
Dependsonoperatingconcfitions.UseNO.2 diesel fuel for
best economy.UseNO.1 diesel fuel (a)whenambienttem-
peratureisbelow320F.,or(b)atalltemperaturesduring
long periodsof light engineload,(c)ifpreferredby user.
Uselowsulfurcontent fuel havinga pourpoint (ability to
filter) ofat least 10OF-belowthelowestexpectedtempera-
ture. . Keep fuel cleanandprotected from adverse weather.
Leave some roomforexpansionwhen filling thetank.
INITIAL START
Checktheenginetomake sure ithas been filled with oil
andthat fuel systemisair-free.
Bleed air from fuel systemas follows: Disconnectthe fuel
WORK TRANSFER PUMP
PRIMING LEVER UNTIL
FUEL FLOWS FROM RE-
TURN LINE FITTING OF
INJECTION PUMP.
return line. SeeFig.14.Operatethehand priming leveron
diaphragmtype fuel, transferpump until therearenoairbub-
blesin fuel flowing from the fuel return line fitting. Then
connectthe fuel return line. NOTE: Ifthecamshaftpump
lobeisup,crankengineonerevolutiontopermithand prim-
ing. Whenfinished,return priming lever inward (disengaged
position) topermitnormalpumpoperation.
Temporarily removetheplug from thewaterpump inlet fitting.
Figure 10. Fill thepump with watertolubricateandprime
it. Replaceplugbeforeoperation.
STARTING
(1) For cold enginestartingabove550F, depress themani-
fold heater switchforoneminute.(2)PushSTART-STOP
switch toitsSTARTposition.(3) Release switchafteren-
gine starts and reaches speed. (4)Oil pressure shouldread
at least 20psi(pressure-reliefvalveisnotadjustable).
Themostcommonfailuretostartis caused by unit running
out offuel—andthennotproperlybleedingthe fuel system
beforeattemptingtostart.
If thesetcontrolhasa re-set button,pushitto re-set
after a shutdownresulting from lowoil pressure or high water
temperatureoccurs. Find the cause beforere-startingthe
engine.Ifcontinuousfalsestartingoccurs,make sure the
centrifugal switch(Fig.16) closes during speed build-up.
Theadjustableresistorslidetap(inthecharging circuit)
is settogiveapproximatelya 2-ampere chargingrate.For
applicationsrequiringfrequentstarts,checkbatteryspecific
gravity periodicallyand,if necessary, increase thecharging
rate slightly (moveslidetap nearer ungroundedlead) until
it keeps thebatterycharged.Adjust only whensetis
stopped. Avoid overcharging.Theresistorislocatedin
thegeneratorairoutlet.
If a separate automaticdemandcontrolforstartingandstop-
ping isused,adjustthecharge rate foritsmaximum4.5
amperes. Thisnormally keeps batterychargedevenifstarts-
occurasoftenas15-minutesapart.
Extremesinstartingtemperaturesmayrequireadditional
preheating.Ifengine fails tostart quickly, rest engine
several seconds and repeat starting sequence applying
preheat fora longer interval.
r^^TI^rXkr^'? ^ notWPhovervoltagetothestarting
CAUTION J .
FIGURE 14. BLEEDING THE FUEL SYSTEM
Idrear t at any time. Overvoltage will
destroy the glow, plugs and air heater in two to three
17

FIGURE IS. OPERATING CYCLE
seconds. II it becomes necessary to use an additional
source ol power to start the unit — use a 12volt battery
connected in parallel.
AUTOMATIC STARTING AND STOPPING
Separate controlsmaybeusedforautomaticstartandstop,
but mustprovideenginepre-heating.
The automatic control hasa timedelayrelaytopre-heat
glow plugsandthe manifold heaterforabout20-seconds
beforecrankingoccurs.Removethejumperintheunit's
control box which connects terminal H (heater)to terminal 3
("start circuit') andconnectseparate-controlpre-heat circuit
to thesetH terminal when installing the control. Thetime
18
delay relayalsodelaysengagementofthestarterwhenload
is re-appliedbeforetheenginestopscompletely.
STOPPING
(1) Pushstart-stop switch tostop position.
(2) Release switch when unit stops.Ifstop circuit fails,
close fuel valve.
APPLYING LOAD
If practicable, allow setto warm upbeforeconnectinga
heavyload.Continuousgeneratoroverloadingmay cause high
operating temperaturesthatcandamagethe windings. The
generatorcansafelyhandleanoverloadtemporarily,butfor
normal operation,keeptheload within nameplate rating. The
exhaustsystemmay form carbondeposits during operationat

light loads. Apply full loadoccasionallybeforeshut-downto
preventexcessivecarbonaccumulations.
Try toconnecttheloadin steps insteadof full loadat
onetime.Mostinstallationsusea line switchthatmustbe
closedtoconnecta portionoftheload.
EXERCISE STANDBY SETS
Infrequent setuseresultsinhardsetting.Operatestandby
seta least 30minutes each week.Runlongerifbattery
needs charging.
BREAK-IN PROCEDURE
The unit shouldberuninthe following sequence:
1. One half hourat1/2load.
2. One half hourat3/4load.
3.FulHoad.
Continuousmnningunderone half loadduringthe first
few hundredhoursusuallyresultsinpoorpiston ring
: seating,causinghigherthannormaloilconsumptionand
blowby.
NOTE: Drain the initial oil alter 50hours ol operation
while the engine is still hot.
SAFETY DEVICES
In case ofdangerously high coolant(water)temperatureor
low oil pressure, the cut-off switch stops the unit. After an
emergencystop,investigateandcorrectthe cause. Press
re-set buttonbeforerestarting.
EMERGENCY OPERATION IF BATTERY FAILS
MDJF generating sets requirea batteryforrunning.Ifthe
setbattery fails completelyandsetmustbeoperatedduring
anemergency,a batterycanbeshared with etherequipment
provided thesetcharging circuit isdisconnectedas follows:
Removetheammeter wire connectedtoterminalNo.8 inthe
control boxand tape the bare end.Theset will notcharge
thebattery with thislead wire disconnected.
HEAT EXCHANGER (OPTIONAL) FILLING
Improper filling ofthe heat exchangercan cause overheating
of theengine.Therefore,topreventthispossibility, follow
these instructionswheneveraddingcoolingtothe heat
exchanger:
1. Remove fill cap.
2. Open fill ventvalve (turn counterclockwise).
3.Removevent plug. (Spec A throughC).
4. Fill with coolant.
5.Close fill ventvalve (turn clockwise).
6.Replacevent plug. (Spec AthroughC).
7.Replace fill cap.
8.Operate unit .10minutesat full load,watchforleaks.
9.Shutdown unit.
Alter running unit 10 minutes, the
closed cooling system is pressurized
and hot. Open the 14 lb. pressure cap slowly to vent
pressure.
10. Slowly open pressure capandcheckwater level.
11. Fill systemtotop with coolant.
OUT-OF-SERVICE PROTECTION
When taking unit outofservicefor30-daysorlonger,proper
storage methodsmustbeusedtoprevent damage from cor-
rosion, contamination,andtemperatureextremes.
Fuel System
1. Cleanaircleaner(if used) - donotserviceaircleaner
with oil. Checkandcleanairintake.
2. Coveror seal exposedairintakeopenings.
3.Cleanthrottlelinkage(andgovernorlinkage)thoroughly.
Lubricate metal ball joints with light machineoil(do
not lubricateplastic ball joints).
Oil System
1. Drain enginelubricatingoil while engineiswarm.Serv-
icetheengine with properoil.TAGtheengineto
IDENTIFY thelubricatingoilinstalled. Secure theoil
filter cap.
2. Rempve fuel injectors.Pour2 ounces ofrust inhibitor
oil (SAE50substitute)into each cylinder.Crankengine
overbyhandseveralrevolutionstolubricatecylinder
walls, pistons,andrings. Install injectors.
3.Removeandserviceoil filter.
Cooling System
1. Drain entirecoolingsystem including watercooledex-
haust manifold andexhaust line. Drain heat exchanger
or keelcoolercomponents,enginecylinderblock,and
waterpumps.
Generatingunitsequipped with heat exchangerorkeel
cooling maybe filled with a goodqualityanti-freezeif
freezing temperaturesareexpected. Drain only those
componentsnotprotected from freezing(exhaustlines,
waterintakeandoutletlines,etc.).
19