Onan J Series Operating manual

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Operators
and
Service
Industrial
Engine
967-0754
JB (SPEC A-T)
JC (SPEC A-V)
1-96
Printed in U.SA
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by any means, is strictly prohibited.

Safety Precautions
It is recommendedthat you readyour engine manualand be-
comethoroughly acquaintedwith your equipment beforeyou
startthe engine.
-\This symbol is used throughout this
manual to warn
of possible seriouspersonalinjury.
-1 This symbol refers to possible equip-
ment damage.
Fuels,electricalequipment,batteries,exhaustgasesandmov-
ingpartspresentpotentialhazards thatcouldresult
in serious,
personalinjury.Takecareinfollowingtheserecommendedpro-
cedures.
SafetyCodes
Alllocal,stateandfederalcodesshouldbeconsultedand
compliedwith:
0 Thisengine isnotdesignedorintendedfor useinaircraft.
Any such use isatthe owner’s sole risk.
General
Provideappropriatefire extinguishersandinstallthem in
convenientlocations.Usean extinguisherratedABC by
NFPA.
Makesurethatallfastenersontheenginearesecureand
accuratelytorqued. Keep guards in position over fans,
drivingbelts, etc.
Ifitisnecessaryto makeadjustmentswhile the engineis
running, useextremecautionwhenclosetohotexhausts,
movingparts, etc.
ProtectAgainst MovingParts
0 Donotwearlooseclothinginthevicinityof movingparts,
suchas PTOshafts, flywheels, blowers, couplings,fans,
belts,etc.
0 Keepyour handsaway from movingparts.
Batteries
0 Beforestartingwork on the engine, disconnectbatteries
to prevent inadvertentstartingof the engine.
0 DO NOTSMOKEwhileservicingbatteries. Leadacidbat-
teriesgive
off a highlyexplosivehydrogengaswhichcan
be ignitedbyflame, electricalarcingor bysmoking.
0 Verify batterypolaritybeforeconnectingbattery cables.
Connect negativecable last.
FuelSystem
0 DO NOT fill fuel tanks while engine isrunning.
DO NOT smokeor useanopenflameinthevicinityof the
engine orfueltank. Internalcombustionenginefuelsare
highlyflammable.
Fuel lines must be of steel piping, adequately secured,
andfree from leaks. Pipingat the engine should be ap-
provedflexible line.
Do notusecopper pipingforflexible
lines as copper
will work harden and become brittle
enoughto break.
Be sure all fuel supplieshavea positiveshutoff valve.
e.
f
ExhaustSystem
0 Exhaustproductsof any internalcombustionengine are
toxic andcan cause injury, or death
if inhaled.All engine
applications, especially those within a confined area,
shouldbeequippedwithanexhaustsystemtodischarge
gases tothe outside atmosphere.
DO NOTuseexhaust gasesto heata compartment.
0 Makesurethat your exhaustsystem isfree of leaks. En-
sure that exhaust manifolds are secure and are not
warped by boltsunevenlytorqued.
ExhaustGas Is Deadly!
Exhaust gases containa poisonousgas that mightcause un-
consciousnessanddeath. Itis an odorlessand colorlessgas
formedduringcombustionof hydrocarbonfuels. Symptomsof
carbon monoxidepoisoningare:
0 Dizziness Vomiting
0 Headache 0 MuscularTwitching
0 Weaknessand Sleepiness
Ifyou experienceanyof thesesymptoms,get out intofresh air
immediately,shutdowntheunitanddo notuseuntilithasbeen
inspected.
The best protection against carbon monoxide inhalation is
properinstallationandregular,frequentinspectionsof thecom-
pleteexhaustsystem.
If younoticeachangeinthesoundor ap-
pearance of exhaust system, shut the unit down immediately
andhaveitinspectedandrepairedatoncebyacompetentme-
chanic.
CoolingSystem
0 Throbbing inTemples
0 Coolantsunderpressurehavea higherboilingpointthan
water. DONOTopen a radiatorpressurecapwhencool-
anttemperatureisabove
212 degrees F (1 00 degrees C)
or while engineisrunning.
9
KeepThe UnitAnd SurroundingArea Clean
e Makesurethatoilyragsarenotlefton or neartheengine.
0 Removeallunnecessarygreaseandoilfromtheunit.Ac-
cumulated grease and oil can cause overheating and
subsequent engine damage and presenta potentialfire
hazard.
r
E-3
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GENERAL INFORMATION
FOREWORD
This manual covers the operation, maintenanceand
service proceduresforthetwo-cylinder, 60cu.
in. 21.6
horsepower JBengine and thefour-cylinder 120cu.
in. 42.5 horsepower JC engine.
The two engines are very similar. Both are 4 cycle,
vertical, in-line, air-cooled engines with overhead
valves. Normalengine speed ranges upto
2700 rpm.
An internal, constant speed, flyball-type mechanical
governor, externally adjustable,
is standard. Optional
two-speed and variable-speed governors are
available.
Eachengineistest-runatthefactoryforseveralhours
and adjusted for correct operation. Any damage
incurred through transit must be corrected before
operating the engine.
f
Unless specified, all instructions and procedures in
this manual apply to both the JB and JC. When
instructionsapply to aspecific enginemodel, referto
theengine nameplate forthemodelandspecification
'
number.
TABLE OF CONTENTS
General Information
.......................... 1
Specifications ................................ 2
Dimensions and Clearances.. ................. 3
Tune-up Specifications ....................... 4
Assembly Torques and Special Tools.. ........ 5
Optional Equipment .......................... 5
Installation ................................... 6
Operation .................................... 9
Troubleshooting Guide ....................... 12
Service and Maintenance ..................... 13
Cooling System .............................. 16
Fuel System.. ................................ 18
Ignition'System.. .............................. 30
Oil System ................................... 41
Flywheel Alternator. .......................... 50
Engine Disassembly and Repair ...............
Wiring Diagrams.. ............................ 66
Governor System.. ........................... 39
Starting System .............................. 44
55
1 WARNING)
EXHAUST GAS IS DEADLY!
Exhaust gases containcarbon monoxide, a poisonous gas that might cause
unconsciousnessanddeath.
It isan odorlessandcolorlessgasformedduring
combustion of hydrocarbon fuels. Symptoms of carbon monoxide poisoning
are:
Dizziness Vomiting
Headache Muscular Twitching
Weaknessand Sleepiness Throbbing inTemples
If you experience any of these symptoms, get out into fresh air immediately,
shut down the unit and do not use untilit has beeninspected.
Thebestprotectionagainst carbon monoxide inhalation is proper installation
andregular,frequentinspectionsof thecompleteexhaustsystem.
If younotice
a change
in the sound or appearance of exhaust system, shut the unit down
immediately and have it inspected and repaired at once by a competent
mechanic.
I
The engine exhaustfrom this product
containschemicals knownto the State
of Californiato cause cancer, birth
I defects or other reproductiveharm.
1
Y
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by any means, is strictly prohibited.

SPEC IF ICAT IO NS
SPECIFICATIONS
Dimension in Inches
MANUAL STARTING ELECTRIC STARTING
JB JC JB JC
I
Height
Width
Length
Weight
Number of Cylinders
Displacement (cu. in.)
26-3/8 28-5/16
17-7/8
1 9-1/2
24-518 37-1/2
220 375
2. 4
60 120
26
I 26
18
- 25
20
37
220
I 375
60
3-1/4
~ ~~
120
3-114
3-5/8
I 3-5/8
Bore
Stroke
H.P.
@ 2700 rpm 21.6
I 42.5
~~
3-1/4 3-1/4
3-5/8 3-5/8
21.6 42.5
I Compression Ratio (Natural Gas Only 9:1 - Spec U & W) I 6.5:l I 6.5:l I 631 I 6.5:l
Connecting Rod Bearings Tri-metal, Replaceable
Main Bearings are Steel-backed, Bronze Sleeve Type;
Replaceable Precision Inserts
STD STD
2 3
STD
I STD
Battery ignition
**Breaker Points and Coil
*'Distributor and Coil
Magneto
*'Flywheel Type
2 13
ff
NA NA
NA NA
STD NA
Gear Driven
Battery Voltage
Combustion Air (CFM)
@ 2700 rpm
STD
I NA
NA STD
NA STD NA NA
12 12 12 12
48
96 48 96
NA
I NA
Inlet Vent
(sq. ft.)
*Outlet Vent
(sq. in.)
Air Cleaner
~ ~~
7 12 7 12
80 160 80
160
DRY DRY DRY DRY
I 1'Coolinn Air (CFM) @ 2700 rDm I 850 I 1250 I 850 I 1250
Fuel Pump Lift (feet)
Oil Filter (Full Flow)
~~~~~~~ ~ ~~ ~ ~~
6 6 6 6
STD STD STD STD
I Choke I Manual I Manual I Manual I Manual
Power Take-Off
Shaft Length (inches)
Shaft Diameter (inches)
4 4 4 4
1-314
1 -3/4 1 -3/4 1 -3/4
I "*Oil CaDacitv. Refill IUS Quarts) I 3 I 6 I 3 I 6
I<eywayWidth
I Keyway Depth
3/8 3/8 3/8 318
3/16 3/16 3/16 3/16
I Kevwav Lenath I 3 I 3 I 3 I 3
- Area when duct is used; without duct, make vent as large as possible.
** - NA means not available.
Plus an additional 1/2 quart when replacing oil filter.
t - For Vacu-Flo cooling: JB-610 CFM @ 1800 RPM. JC-1600 @ 1800 RPM
ttt -
2
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DIMENSIONS AND CLEARANCES
All clearances given at room temperature of 70°F .
All dimensionsin inches unless otherwise specified .
CAMSHAFT
Bearing Journal Diameter. Front ..........................................
Bearing Journal Diameter. Rear ..........................................
Bearing Journal Diameter. Center (JC) ...................................
Bearing Clearance Limit .................................................
End Play. Camshaft ......................................................
Cam Tappet Hole Diameter (Prior to Spec P) .............................
Cam Tappet Hole Diameter (Begin Spec P) ...............................
Cam Tappet Diameter (Prior to Spec P) ...................................
Cam Tappet Diameter (Begin Spec P) ....................................
CONNECTING RODS
Large Bearing Bore Diameter ............................................
Small Bushing Bore Diameter ............................................
Distance. Center Large Bearing Bore to Small Bushing Bore ...............
Clearance. Large Bearing to Crankshaft ..................................
Piston Pin Bushing Inside Diameter (bushing reamed) .....................
CYLINDER
Cylinder Bore Honed Diameter .............................................
MaximumAllowableTaper ................................................
Maximum AI lowableOut- of - Round .........................................
CRANKSHAFT
Main Bearing Journal Diameter (JB) ......................................
Main Bearing Journal Diameter (JC) ......................................
Crankshaft Main Bearing Clearance (JB) ..................................
Crankshaft Main Bearing Clearance (JC) ..................................
Connecting Rod Journal Diameter ........................................
Connecting Rod Bearing Clearance ......................................
End Play. Crankshaft ....................................................
PISTON
Piston Clearance to Cylinder Wall ........................................
PISTON PIN
length ........................................................
Diameter ................................................................
Piston Pin in Piston ......................................................
Connecting Rod Bushing Clearance .......................................
PISTON RINGS
Ring Type
Top
.................................................................
2nd .................................................................
3rd ..................................................................
Ring End Gap ...........................................................
VALVE INTAKE
Stem Diameter ..........................................................
Clearance in Guide ......................................................
Seat Angle ..............................................................
Minimum
2.500
1.1875
1.2580
. 0012
. 007
. 7505
. 8755
. 7475
. 8725
Maximum
2.505
1.1 880
1.2582
. 0037
.039
. 7515
. 8765
. 7480
. 8730
2.1871 2.1 876
1.044 1.045
5.998 6.002
. 001 .003
. 9903 . 9906
3.2495 3.2505
0.005
0.002
2.2437 2.2445
2.2427 2.2435
. 0014 . 0052
. 0024 . 0062
2.0600 2.0605
. 0010 . 0033
. 010 .015
. 0012 . 0032
2.753 2.738
. 9899 . 9901
. 0002 . 0007
Thumb Push Fit
Compression
Compression
Oil Control
. 010 .020
. 3405 . 3415
. 001 .003
. 42'
VALVE. EXHAUST (Stellite Faced)
Stem Diameter ........................................................... 3405 . 3415
Clearance in Guide ...................................................... -0030 . 0050
Seat Angle .............................................................. 45"
3
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VALVE GUIDE
Length . . . . . . ...... . . . ... . ....... . . . . .. . .. . . . ... . ........ . .. . . . ... ... . . ..
Outside Diameter. .. .. . . .... . ... . ..... . . .. . . .... .. . .. .. . . . ...... . ... .. . ..
Cylinder Block Bore Diameter.. .. .. . . . ...... . . . . . . . . . . . .. . . . . .... . . . .... .
Inside Diameter (after Reaming)
Exhaust
........................................... ....: :............
Intake ...............................................................
VALVE SEATS (Stellite)
Valve Seat Bore (diameter)
Intake
...............................................................
Exhaust .............................................................
Depth (from Cylinder Head Face). . . . . ... . . .. .. . ... . ..... . .... . .. .. ...
Seat Outside Diameter
Exhaust
.............................................................
Intake ...............................................................
Seat Width . ... . . . .. . . . . ... .. . . . . . ... ... .. ... . . . ..... . .. . . . .... .. ... . . ...
Seat Angle ... .. . .. . . .. . . ..... . . . . . . . . .. . .. .. . . . . .... . . . .. .. . ... . ... . . .. .
Available Oversizes .. ... .... .. . . .'. .... . ... . . ... ... . .. . .. . ... :. ....... . . . .
VALVE SPRINGS
Free Length ................................................................
Length, Valve Closed ....... . .. . .. . .. . . . .. .. ... . . . . . , ... .. ...... . ...... . .
Load, Valve Closed ......... . .. ...... . . . .. . .. . .... . ........... . . . .... . .. .
Length, Valve Open.. .... . .. . . . . , . .. .. .. . .. . . ... .. .......... .. . . ....... . .
Load, Valve Open.. . . ........ . .... . . . . . . ... . . . . . . ....... . .. . ..... . . . .....
Valve Stem to Guide (intake) . . .. . . ... . .... .. . .. ...... . . , . . . .... .. ........
Valve Stem to Guide (exhaust) .. . . ... ..... . . , .. .. ........... . ............
Valve Face and Seat Angle.. . . .. . ... . . ...... . .. . . .. ..... .. ...... . .... . ...
Valve Spring Tension
Valve open
.- Prior to Spec P . . .. . .. .. . ... .. . . . . ..... . . .. .... . .. .. ...
Spec P and later.. .. .. ....... . ... . ... . . . .... ... . ...... . ... .
Valve closed - Prior to Spec P.. ... ... . . . . ... .. ...... . . .. . ....... . . . ..
Spec Pand later.. .. .. , ..... . . .. . .. .. ....... . .. ....... .. . ..
Distributor Stem Diameter (JC). ... . .. .. . . . ..... . ... . . . . . . . . . . . . . ....... . .
Distributor Hole Diameter (JC) . . . . . . . . . . . . . . . . .... ..... . . .. ... . .. . ... . ...
1 -25/32
.4690 .4695
.467 .468
.344 .345
.342
' .343
1.547 1.548
1.361 1.362
.433 .439
Tune-up Specifications
Valve Clearance - Intake (cold - 10" to 45" ATC on power stroke)
Prior to Spec C..
........ ..... . .... . ... .. . . .. . .. .. ... .. ....... . . .-. . ...
Begin Spec C ... . ..... .. . .'. .. ... . . . ... . . . .. . . . ... .. .. . . . . .. . . . . .. . . .
Valve Clearance - Exhaust (cold - 10" to 45" ATC on power stroke)
Prior to Spec C..
..... . . . . . . . .. . . . . . . .. . . . . .. . . . ............ . .... . ...
Begin Spec C . . .......... . . . . . .. . .... . . .. . . .... . . ..... . . . . .. . . .. ....
ONAN Ignition Breaker Point Gap.. . . . .. . .. ... . .. .. . ..... . . . ....... . . . . . .
WlCO Magneto Breaker Point Gap ... . . .. . .. .... ... . . . . . . .. . .... . . .. .. . . .
Distributor Breaker Point Gap (JC) . .. . . . ... .. ... . ..... . , .. .. ... . ... . . . . . .
Spark Plug Gap:
JB
... . . . . . ... . . .. . .. . .. . . .. . .. ...... , . . ... . .. .. . . . .. .... . .. ........
JC . . . . .. . . . . . . ... . . . .... . . . . ..... . . . .. ... . .... . . . ... . .. .. .... . ... . .
Start-Disconnect Switch Point Gap . . . . . . . . . ... . ... . . ... . .. , . . . . . ... .. . ...
Ignition Timing Spark Advance - 25"BTC for gasoline,
Firing Order (JC)
. ... . . ... . . . .. , .. . ...... . . . .... , . . ..... , . ... . .. . .. . .. . ..
35"BTC for natural gas, LPG, or combination gadgasoline
1.364 1.365
1.550 1.551
3/64 1/16
45
"
.002, .005, .010, .025
1 -7/8
1.528
45-49
I bs.
1.214
83-93
Ibs.
.0005 .0025
.0025 .0045
45
"
83 Ibs. 93 Ibs.
87.2 Ibs. 97.2 Ibs.
45
Ibs. 49 Ibs.
45
Ibs. 49 Ibs.
1.061 1.062
1.063 1.064
.010
*.012
.013
**.015
.02Q
.015
.018-.022
.025
.035
.020
1-2-4-3
* - Exception: with natural gas fuel, intake is ,013.
** - Exception: with natural gas fuel, exhaust is ,020.
.4
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ASSEMBLY TORQUES AND SPECIALTOOLS
ASSEMBLY TORQUES
The assembly torques given herewill assure proper
tightness without danger of stripping threads. If a
torque wrench isnotavailable, becarefulnottostrip
threads. Use reasonable force only and a wrench of
normal length.
Specially designed place bolts do not require a
lockwasher or gasket. Check all studs, nuts and
screwsoftenandtightenas neededtokeepthemfrom
working loose.
1
TORQUE SPECIFICATIONS (Ft. Lbs.)
Center Main Bolt (4 cylinder). ............. 97-102
Connecting Rod Bolt ...................... 27-29
Cover-Rocker Box .......................... 8-10
Cylinder Head Bolt ........................ 28-30
Exhaust Manifold Nuts.. .................. 13-15**
Flywheel Mounting Screw. ................. 65-70
Hub-to-Flywheel Screws (4 cylinder) ....... 17-21
Fuel Pump Mounting Screws.. ............. 15-20
Gear Case Cover .......................... 18-20
Intake Manifold. ........................... 13-15
Oil Base Mounting Screws ................. 45-50
Oil Filter ................... Hand Tight + 1/2 Turn
Oil Pump Mounting Screws
................. 15-20
Rear Bearing Plate.. ....................... 40-45
Rocker Arm Nut.. ......................... 4-IO*
Rocker Arm Stud .......................... 35-40
Spark Plug ................................ 25-30
PLACE BOLTS
SPECIAL TOOLS
Thesetoolsare availablefrom ONAN toaidserviceand
repairwork.
Driver,Valve Seat
....................... .420-0270
OilSeal Guide and Driver.. .............. .420-0456
Valve Seat Remover. .................... .420-0311
Replacement Bladesfor 420-0272 ........ .420-0274
CrankshaftGear Pulling Ring ............ .420-0248
Driver, Center Camshaft Bearing (JC only) . .420-0254
Driver, Combination Mainand Cam ........ .420-0326
Reamer, Ridge. ......................... .420-0260
Valve Guide Removerand Driver ......... .420-0300
- This torque isfrornfrictionbetweenthethreadsonlyand locks
the nuts in place. The rocker arm nuts are
for adjusting valve
lash.
- I lyiliari riuis averiiy io avoia rnaniioio oarnage.
.. -.
OPTIONAL EQUIPMENT
1. Solenoid Shift Starting Motor - 12 volt or 24-32
volt; less solenoid switch.
2. Auto-Cycle Starting Motor - 12 volt DC or 120
volt AC; 18 to 1 gear reduction; gear train
lubricated bycrankcaseoil; one-way, sprag-type
engaging clutch.
3. Flywheel Alternator - For battery charging;
integral; no brushes or commutator; two step
regulator; maximum charge rateat 2400 rpm; 14.5
amperes into 70 AH discharged battery.
4. Low Oil Pressure Cut-Off - Shuts down plant if
oil pressure fails. Crankcase oil level must be
checked regularly.
5. Two-Speed Governor - Twospringsfor low-and
high-speed control of engine.
6. Gas-Gasoline Carburetor - One carburetor with
gasoline and gaseous fuel provisions. Available
as a factory modification or
as afield conversion
kit.
5
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GENERAL
The initial installation is very important. Plan it
carefully to ensure maximum operating efficiency.
Use this manual as a general guide. Recommen-
dations are based on extensive tests underfavorable
operating conditions. Conform to local, state or
federal codes regulating the installation and opera-
tion of internal combustion engines.
LOCATION
Engine location isdeterminedchiefly bytheintended
application. Provide adequate access for service and
repair. Protect the engine from adverse weather.
Consider location of related systems, such as fuel,
exhaust and ientilation.
MOUNTING
Secure the engine to a rigid, level foundation. See
Figures
1 and 2for typical installations. Foundations
must besturdy enough to withstand distortion andto
retain alignment with related equipment.
If necessary to exceed 23 degree tilt angle, consult
factory for maximum allowable angle. Compensate
for any tilt when checking crankcase oil.
VENTILATION
Providesufficient fresh airintakeandexhaust ventila-
tion to support combustion and cool the engine and
generator. Avoid recirculation of ventilating air to
preventengineoverheating.See
Specifications forair
flow requirements and vent sizes.
Locate vents
so the flow of air from the inlet to the
outlet passes over the engine. The outlet should be
slightly higherthan the inlet.Allow for heatproduced
by related equipment. See Figures
1 and 2.
An optional air shutter may beusedattheoutlet vent
to control enginetemperature by regulating air flow.
Air shutters also prevent the backflow of cold air
during engine shut-down.
When air ducts are used between the engine and
outlet vent, use a section of canvas to restrict
vibration, as shown in Figure 2.
EXHAUST
WAGIN ING
Exhaustgasispoisonous.Pipeexhaustgases
u outside. Exhaust pipes must not terminate
near ventilationsystem inlet vents.
1. Avoid sharp bends.
2. Use sweeping, long-radius elbows.
3. Use a section of seamless, flexible tubing
between theengineandany rigidpipingtoisolate
vibration.
4. Increase pipes one size for each additional 10-
foot span.
5. Protect walls and partitions through which ex-
haust pipes pass with a metal thimble, Figure 2.
Install a suitable muffler, preferably as close to the
engineas possible.Pitchexhaust pipesdownward,or
providea condensation trap at the pointwhere a rise
in the exhaust system begins.
.
f
Some installations may require unusually
long exhaust pipesand/or numerouselbows.
A poor exhaust system will increaseback pressureat the engine,
and can cause low engine power with reduced efficiency,
overheatingand eventualdamage.
To check exhaust back pressure, install a tee or
adapter inexhaust line nexttothemanifold. Connect
a manometer or pressure gauge to the adapter. If
there isacondensationtrap nexttothe manifold,this
fitting can be used for connecting the manometer.
Permissible maximum back pressure is 27” water
column (2“ mercury)atfull loadfor all models.Atno-
load, maximum limit is
5.1” water column (3/8“
mercury) for the two-cylinder and 4.7“ water column
(1/3” mercury)for thefour-cylinder engine. Check at
full load for the best measurement. If the reading is
higher than maximum limit, the exhaust system
should be disassembled and cleaned or altered to
reduce back pressure.
GASOLINE FUEL
Locate separate fuel tanks no lower than six feet
belowtheengine fuel pump. Auxiliaryfuel pumpsare
,
available to provide an additional six-foot lift.
To preventfuel loss and fire hazards due to
tziiIl leaks from line breaks, avoidgravity feed of
fuel to the engine from tanks not mounted on the engine.
WARNING
Whensharingafueltank,donotconnectlines
*
at a point above the fuel supply level to
preventstarving the engine.
Install the fuel supply line from the tank to the 1/8”
pipe inlet in the fuel pump. Usean approved flexible
fuel line at the fuel pump to absorb vibration.
Fuel supply line must be leaktight. Install a shut-off
valve at the fuel tank for service convenience. Run a
vent pipe from the fuel tank to the outside of the
compartmentto removegasolinefumestotheoutside
atmosphere.
?
6
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ACCESS
DOOR
FIGURE 1. MOBILE INSTALLATION
METAL THIMBLE
FIGURE 2. STATIONARY INSTALLATION
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GASEOUS FUEL
Check with your supplier for localregulationscover-
ingtheuseandhandlingofgaseousfuelsuppliesand
equipment. Seal gas line connectionswith shellac or
some other compound approved for use in gaseous
fuel systems. Thread-sealing compounds with a lead
base are not satisfactory. Engineswith electric con-
trols may require a solenoid primer and
a shut-off
valve.
Install a manual shut-off valve as thefirst component
in the supply line. Install a “dry gas” filter and fuel
solenoid valve if recommendedby your gas supplier
or local code. Install the demand-type regulator
according to the instructions supplied. Use shortest
. possible hose between the regulator and carburetor
for best starting. See Figure
3.
CARBURETOR
GAS REGULATOR
.4
G-4 SOLENOID VALVE
FIGURE 3. GASEOUS FUEL SYSTEM
OIL DRAIN EXTENSION
Forservice convenience, installanoildrainextension
in the
1/2 inch pipe-tapped oil drain hole in the oil
base. Use standard
112 inch pipe and fittings.
BATTERY
Mountthe batteryonawooden ormetalrack nearthe
engine. Air circulationaroundthebatteryisessential.
Use battery cables of proper length to limit voltage
drop. Coat connections on the battery with vaseline
or grease to prevent corrosion.
b
BATTERY CONNECTIONS
On engine with flywheel alternator, ground the
negative terminal of the batteries to the engine.
Failure to ground the battery negative ter-
minalwill result
in destruction of theselenium
rectifiers.
Connectionof battery.positiveterminals depends on
the type of starting motor used for cranking, as
follows:
1. Bendix (standard on cranking models): Connect
positive from a suitable source of DC to start
switch. Connect negative
to a good ground on
engine.
2. Solenoid Shift (optional on cranking models):
Connect positivefrom asuitableDCsourceto B+
terminal on start solenoid. Connect negative to a
good ground on engine.
3. Auto-cycle (optional on crankingmodels): 12 volt
DCand
120 volt AC starters have 2 wire connec-
tions through a sensing device for automatic
starting.
8
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0 PER AT1 ON
PRE-STARTI NG
Preparations for the initial and each additional star-
ting operation should include careful checks of the
Oil, fuel, cooling, andelectricalsystems.Thecylinder
air housingdoorshould beclosedwithallairshrouds
in place.
remove, clean
in solvent, dry thoroughly and install.
Heavyexhaustsmoke when theengineisfirst started
is normal and is caused bythe inhibitor oil.
Use extreme caution when cleaning with
1 -WARNING 1 petroleum-base cieansersdue to fire hazard.
Before generator set is put in operation, check all
components for mechanicalsecurity. If an abnormal
condition, defective part, or operating difficulty is
detected, repairorservice as required. Thegenerator
set should be kept free of dust, dirt, andspilledoilor
fuel. Besu.reproperoperating procedureisfollowed.
4
CRANKCASE OIL
Use a heavy duty detergent oil that meets the API
(American Petroleum Institute) service designations
MS, MS/DG, SE or SE/CC. Oil should be labeled as
havingpassedthe
MS SequenceTests(alsoknownas
theASTMG-IV SequenceTests)andtheMIL-L-2104B
Tests. Recommended SAE oil numbers for expected
ambient temperatures are as follows:
30" Fto 90" F
0°F to 30°F SAE 1OW
Below 0°F
SA€ 30
SAE 5W (5W-30 if
5W is not available)
Do not use service
DS oil. Do not mix brands nor
grades. Refer to
Maintenance section for
recommended oil changes.
RECOMMENDED GASOLINE
Use clean, fresh regular grade, automotive gasoline.
For new engines, most satisfactory results are ob-
tained by using nonleaded gasoline. For older
engines that have previously used leaded gasoline,
headsmustbetakenoffandall leaddeposits removed
fromengine beforeswitchingto nonleaded gasoline.
If lead depositsare not removedfrom engine
before switching from leaded to nonleaded
gasoline, pre-ignition could occur causing severe damage to the
engine.
To preventhazardousgasolinespillage,never
fill the tank when the engine
is running and
leavesomefuelexpansionspace.Observesafetyprecautionswhen
handling gasoline.
INITIAL START
Check the engine to make sure it hasbeenfilledwith
oilandfuel. Cylinderairhousingdoormustbeclosed.
If enginefailstostartatfirst attempt, rust inhibitor oil
usedatthefactory mayhavefouledthespark plugs-
STARTING
1. Push srart-slop switch to start position.
2. Releasetheswitchafterenginestartsand reaches
3. Oil pressure gauge should read at least
20 psi
speed.
(pressure relief is not adjustable).'
If the unit control has a resetbutton, push it to reset
only after a shutdown resulting from oil pressure
failure occurs. Find the cause before restarting the
engine. On early sets, reset or temporarily switch to
manual to start after oil filter change.
Leave
elec start-handcrank switchat ekc start position.
This avoids battery discharge.
Exception: While
emergency hand-cranking, switch to manual start
position, then return switch to
elec start positionafter
starting. (Older models with manual start only.)
If a false start occurs with a starter motor equipped
set, make sure the centrifugal switch closes during
speed build-up.
Extremes in starting temperatures may require a
slightelectricchokeadjustment. Ifenginefailstostart
quickly, rest engine several seconds before
successive cranking attemptsto allow choketo cool
and close.
STARTING SEQUENCE
Thestarting andstopping (Figure4) sequenceshows
the manual, mechanical, and electrical events re-.
quired for satisfactory start, run, and stop cycles.
ELECTRIC CRANKING
1. Turn ignition switch on.
2. Set hand choke as required by temperature.
3. Engage START switch.
4. Release START switch when engine starts.
5. See that oil pressure is at least
20 psi (not
adjustable)
.
6. Readjust manual choke as engine warms up.
Do not apply overvoltage to the starting
ExzI circuit at any time. If itbecomesnecessaryto
use an additional source
of power to start the set - use a 12 volt
battery connected in parallel.
CAUTION
9
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17
1’ . io
FIGURE 4. OPERATING CYCLE
MANUAL CRANKING (Older Models)
1.
2.
’ 3.
4.
5.
6.
7.
Prime carburetor. Make certain priming lever is
down when finished.
Set hand choke as required by temperature.
Engage crank with crank dog.
Position crank handle at
7 o’clock.
Pull crank with hard, steady pull to
12 o’clock.
See that oil pressure is at least
20 psi.
Readjust choke as engine warms up.
ENGINE SHUT-DOWN
Disconnectas much loadas practicalfromtheengine
before shut-down. Stop engines having momentary-
contact Stop switches by holding switch to Stop
position until engine stops completely. Releasing
switch beforeengineisfullystoppedwillallowengine
to continue to run.
APPLYING THE LOAD
Apply the loadfor new and reconditioned engines in
four steps. Wait
30 minutes between each step.
Maximum endthrust onthe mainbearingsshouldnot
exceed
1000 pounds.
INSPECTION
Check for alignment of engine and load. Misalign-
mentwill cause excessivevibrationandbearingwear.
Make a visual inspection of the entire installation.
OPERATION WITH GAS-GAS0 CAR-
BURETORS
Gas-gas0 carburetors installed at the factory are
adjusted with
1000 BTU natural gas. Readjust the
carburetor when using gas of adifferent BTU rating.
Readjust the carburetor when operating above
2500
feet for best fuel/air mixture. Derate engine power 4
percentfor each 1000 foot increase in altitudeabove
1000 feetfrom sea level.Makenecessaryadjustments
only after checking engine performance.
CHANGING TO GASOLINE
Use the following procedure to change from gas to
gasoline:
1. Close gas supply shut-off valve.
2. Open gasoline supply shut-off valve.
3. Unlock optional electric choke.
4. Start engine; follow normal procedure.
CHANGING TO GAS
Usethefollowing procedureto changefromgasoline
to gas:
1. Close gasoline supply shut-off valve.
2. Open gas supply shut-off valve(ontheinitialstart
only,operatethe primertoforceairfromtheline).
3. Open manual choke (optionalelectricchokeheld
open by lock wire inserted through hole inchoke
shaft). Choking not required. Starting at low
temperatures may be aided bypressing priming
button on Algas regulator.
4. Start engine; follow normal procedure.
HIGHTEMPERATURES
1. See that nothing obstructs air flow to and from
engine.
2. Keepcooling fins clean. Seethatair housingsare
properly installed and undamaged.
3. Keep ignition timing properly adjusted.
4. Be sure fuel-air mixture gives best operation.
LOW TEMPERATURES
1.
2.
3.
4.
Use proper SAE No. oil for temperature con-
ditions. Change oil only when warm from run-
ning. If an unexpectedtemperature dropoccurs,
move engine to a warm location, or apply
flamelessheat directlytocrankcaseuntiloilflows
freely.
Usefresh, regular (not“premium” type)gasoline.
Protect against moisture condensation. Below
0” F, opencarburetormainjetoneadditional turn.
Keep breaker points and spark plugs clean and
properly adjusted. Keep batteries
in a well-
charged condition.
Partially restrictflow of coolingair. However, use
care to avoid overheating.
10
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DUSTAND DIRT
1. Keep engine clean. Do not allow cooling fins to
2. Service air cleaner as frequently as necessary.
3. Changecrankcase oilevery 100 operating hours.
4. Keep oil and gasoline supplies in dust-tight
become coated or obstructed with debris.
containers.
.
5. Keep governor linkage connections clean.
HIGHALTITUDE
For operation at altitudes of 2500 feet or more, close
the carburetor main jet adjustment slightly to main-
tain proper air-to-fuel ratio. Refer to the
Aa'jusfmenrs
section. Maximum power will be reduced about 4
percent for each 1000 feet increase in altitude.
*
PROTECTION FOR EXTENDED OUT-OF-
SERVICE PERIOD
Protectan engine that isto beout-of-service for more
than
30 days as follows:
1. Run engine until thoroughly warmed up.
2. Turn off fuel supply and run until engine stops
from lack of fuel.
3. Drain oil from oil base while still warm. Attach a
warning to refill before operation.
4. Remove each spark plug. Pour one ounce (two
tablespoons) of rustinhibitor (orSAE#50)
oil into
cylinder. Crank engine over afew times. Leaveat
top center position. Reinstall each spark plug.
5. Service air cleaner.
6. Lubricate governor linkage. Protectagainst dust,
etc. by wrapping with a clean cloth.
7. Plug exhaust outlet to prevent entrance of
moisture or dirt.
8. Wipe entire unit clean. Coat parts likely to rust
with a light film of grease or oil.
9. Provide a suitable cover for entire unit.
storage procedure.
10. Disconnect battery and follow standard battery
Discharged batteries are subject to severe
damage
if exposed to freezingtemperatures.
Storeallbatteriesina
fully chargedconditionandmaintaincharge
during storage.
RETURNING THE SET TO OPERATION
1. CHECK SERVICE IDENTIFICATION TAGS to
properly service the set.
2. Uncover and remove all storage seals from unit.
Remove any dust, dirt, or foreign matter.
3. CHECK fuel supply tanks for moisture ac-
cumulations (drain tanks if necessary). CHECK
lubricating oil for moisture or contamination
(drain if necessary). CHECK fuel line connec-
tions, all wiring connections, and exhaust line
connections.
4. Service air cleaner (ifused). Bleedfuel system (if
moisture or contamination are found
in fuel,
replace filters and clean fuel pump sediment
bowl).
5. Check tag on oilbase and verifythatoilviscosity
is still correct for existing ambient temperature.
6. Clean andcheckbattery.Measurespecificgravity
(1.260at 25" C
(77" F) andverifylevel io beatsplit
ring. Ifspecific gravity islow, charge untilcorrect
value isobtained. Iflevelislow,adddistilledwater
and charge until specific gravity is correct.
DO
NOT OVERCHARGE.
Do not smoke while servicing batteries.
I Explosive gases are emitted from
batteries in operation. Ignition of these gases can cause
severe personalinjury.
leakage as required.
7. Check entire unit for fuel or oil leaks. Correct
8. Install fully charged batteries.
9. Start set innormal method. Check while running
set for leaks, correct voltage output, proper
cooling
.
After engine has started, excessive blue smoke will beexhausted
and the engine will run rough until the rust inhibitor or oil has
burned away.
.
11
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‘,TROUBLES c - H 0 OT IN G G Lb ID E
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SERVICE AND MAINTENANCE
The following maintenance isrecommended to keeptheengine in
tion. recommended fuel and oil, norma!load, etc. See Table 1.
C.
good condition. Neglect of routineservice may result in failure of
the engine at a time when itisurgentlyneeded. Thechart isbased
on unitsoperating underfavorableconditionqwithproperinstalla-
D.
SERVICE NOTES
These supplement the Pu-iotlic. Service Cliurr.
A. Inspect for leaks, loose connections, etc. Keep
Engine Clean.
B. FUEL SUPPLY. Check supply to avoid running
outof fuel. Neverfill tank while engineisrunning.
Use clean, fresh "regular" gradegasoline. Never
fill completely; allow some spacefor expansion.
E.
OIL LEVEL. Keep level to F (full) mark on
indicator, Figure
5. Whenadding,usesamebrand
and type as in crankcase.
GOVERNOR LINKAGE. Plastic-type joints re-
quire cleaning only. On metal-type joint, use
lubricating graphite on ball joint, Figure 6, and
link-to-throttle. If graphite is notavailable,use a
light machine oil, Figure 6.
AIR CLEANER. See Figure 7.
1. Foam type-Wash element insuitable solvent
or diesel fuel every
200 hcurs. Saturate with
engine oil and squeeze as dry as possible.
2. Oil Bath-Clean cup and refill to indicated
level with same grade of oil as used in
crankcase.
TABLE 1. PERIODIC SERVICE CHART
- Service more often under'extreme dust conditions.
+ - See service note F.
E - Tighten head bolts and adjust valve clearance after first 50 hours
t - See service note L.
*' - With engine running, visually and audibly check for
fuel and exhaust leaks which are a potential hazard.
See Note
N.
on a new or overhauled engine.
13
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/ ALWAYS REPLACE CAP
IGHTLY, OR OIL LEAKAGE
MAY
OCCUR.
THIS LEVEL
FIGURE 5. OIL LEVEL
AFTER WASHING ELEMENT IN
SOLVENT DIP IN ENGINE OIL AND
SQUEEZE AS DRY
AS POSSIBLE
FIGURE 7. AIR CLEANER ELEMENT
"5r SHIFT SLEEVE
FIGURE 6. GOVERNOR LINKAGE
F. CRANKCASE OIL. Change oil only when warm
after operating. If oil is too cold to flow, do not
start engine. Move to a warm location or apply
flameless heatexternally untiloilflows freely. Oil
Filter is a full-flow type.
Change oil every
100 operating hours when
operated in extremely low temperatures, under
extreme dust or dirt conditions, when using
highly leaded gasoline, or running for short
periods of time.
G. BREATHERVALVE. Thebreather valve maintains
a partial vacuum in crankcase. If faulty, install a
new valve. Lift off rubber breather cap, Figure 8.
Carefully pry valve from cap, or squeeze top of
cap to release valve from rubber cap. Wash this
fabric flapper-type check valve
in fuel. Dry and
reinstall with perforated disc toward engine.
A
flapper valve is not used on JC engines.
H.
SPARK PLUGS. Removespark plugs. Clean and
adjust electrode gap. See
Dimensions and
Clearances.
If engine runs rough or if plug fails to
pass a standard test, install new spark plugs.
I. BREAKER POINTS. Refer to Tune-up
Specijications
for correct gap. Replace burned or
faulty points. If only slightly burned, dress
smooth with file or fine stone. Measure gap with
thickness gauge.
Ignitionbreaker points mustbecorrectlygapped.
Crank engine to fully open breaker points
(1/4
turn past top center for JB). Loosen and move
stationary contact to set correct gap. Retighten
and recheck gap.
Ignition points should break contact just as
timing mark aligns with degreeof spark advance
14
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J.
K.
L.
JB SERIES, PRIOR TOSPEC. S AND
ALLMODELS PRIOR TOSPEC T
NOTEFLAPPER VALVE IS NOT USED
ON JCSERIES. JC SERIES USE PCV
VALVE BEGINNINGSPEC
T.
BREATHER TUBE
UBE BAFFLE
CRANKCASE BREATHER
Remove breather cap. Remove valve from
cap. Wash valve in solvent. Dry and install
with perforated disc toward engine.
If
faulty, install new valve.
FIGURE
BREATHER HOSE
BREATHER HOSE
INSULATOR
CAPAND
VALVE.
1
"0" RING ,
/HOSE CLAMP
CLAMP
1
SCREEN
BAFFLE1
BR
1
ISULATOR
CRANKCASE
BREATHER
(BEGIN SPECS)
A178
Remove hose clamp.breather hose.breather cap clamp
and insulator halves to release breather cap
and valve
assembly. Wash cap
and valveassembly and the baffle
in suitable solvent and reinstall.
8. BREATHER VALVES
specified in Tune-upSpecij7cations. Replace con-
denser if spark is weak or if points burn readily.
BATTERY. Check charge condition. Check elec-
trolyte level. Add distilled water to keep elec-
trolyte at itsproper level. In freezingweather, run
engine immediately after adding water. Keep
battery connections tight and clean.
FUEL SEDIMENT. Empty carburetor and fuel
filter (strainer) bowls of any accumulated sedi-
ment. Clean filterscreen thoroughly. Reassemble
and check for leaks.
OILFILTER. Theoilfilter isafull-flow type (alloil
isfilteredenrouteto bearings).A by-pass permits
unfiltered oil to reach bearings if filter becomes
clogged. Placeadrippanbelowfilter. Unscrewoil
filter counterclockwise, using both hands or a
filter wrench (box-end orstrap-type). Clean filter
mountingarea. Lubricatefiltergasketwithengine
oil. Turn new filter on hand tight, then
1/2 turn
further, usingafilter wrench.
Do notovertighten.
Change
oil filter more often if oil becomes too
dirty to readdipstick markings. This can happen
M.
N.
under extreme dust conditions or in-freezing
temperatures. When adding newoiltocrankcase,
allow an additional 1/2 quart for oil filter.
MAJOR ENGINE SERVICE. Remove carbon and
lead deposits from combustion chamber, valves,
etc.asoftenas experiencedictates,dependingon
operating conditions. Adjust valve clearances
when cold. Flush rocker box cover oil line in
solvent and clean small holes using fine wire (do
,
not enlarge holes). Clean entireengine toensure
efficient cooling and operation. Perform other
services as inspection or operation shows
necessary.
EXHAUST SYSTEM. Makeregular inspectionsof
the exhaust system throughout the entire life of
the engine. Locate leaks in muffler and piping
while the engine is operating.
Leaky exhaust systems emit noxious
carbon monoxide fumes which are a
potentialhealth hazard in enclosed areas.
15
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CQOLING SYSTEM
JBandJCengines useapressure-aircoolingsystem.
Blades on the engine flywheel draw air into the front
of the engine housing and force itpast the cylinders
and out the right side of the engine. The engine air
outlet may use an air duct and an optional shutter
assembly. Figure
9 shows the air tlow through the
engine housing.
MAINTENANCE
Clean the enginecooling area (finson cylinder block
2nd cylinder heads) at regular intervals, normally
every 1000 hours, but more often under dirty
operating conditions.
OVERHEATING
Thefirst signs of Overheatingareusually indicatedby
dark exhaust smoke,
loss of engine power, and a
speed
loss. If possible,theengineshould bestopped
at the first sign of speed or power
loss before the
engine seizes.
The most probable causes of overheating a.re dirty
cooling surfaces, operating without the engine air
housing, poor air circulation, improper lubrication
and/or engine overload.
The air housing,includingthe door, must be
on when operating the engine. Overheating
and permanent damage can resultfrom as little as one minuteof
full-load operationwithout
it.
The most common installation problems leading to
overheating are:
1. Installation with duct sizetoo small for sufficient
air flow.
2. Installation in a small room with no ducts and
insufficient air vent
i I ation.
3. Air inlet and outlet ducts positioned so air outlet
feeds back to the inlet.
AIR SHUTTER (Optional)
Theshutter assembly mountsontheengineairoutlet
on the rightsideof thecylinder shroud (Figure 10).A
thermostatic element(Figure 11)controls theshutter
closing, which limitsair flow when theengine
is cold.
When the airtemperature reaches 120" Ftheelement
plunger begins to move outward, opening the
shutters. The shutters arecompletelyopen by140OF.
Onearly models, a high temperature cut-offswitch mounts on the
air shutter assembly.
BLOWER
BLOWER WHEEL
FIGURE 9.
PRESSURE AIR COOLING SYSTEM
16
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AIR DUCT
FIGURE 10. OPTIONAL AIR SHUTTER
Theshutteropeningtemperatureisn’tadjustable. The
power element plunger must contact the shutter roll
pinat roomtemperature. To adjust,loosenthepower
element mounting screws and slide the assembly
until it touches the roll pin with the shutter closed
(Figure
11).
VERNATHERM BRACKET
ADJUSTING AND MOUNTING
SCREWS INSLOTTED HOLES.
-
ADJUST THE VERNATHERM
POWER ELEMENT TO REST
ON THE ROLL PIN WITH
SHUTTER CLOSED AT AMBIENT
TEMPERATURE
REPAIR
If theshutterwon’t open, checkthepowerelementfor
defects or binding of the plunger. Check theshutter
for binding against the housing.
To test the power element, remove it from the
assembly and apply heat. When theelement reaches
about 120°F, the plunger should start to move out.
Total movement should be at least 13/64-inch.
If the shutter won’t close, check for a weak return
spring, binding
in the nylon bearings, or dirt in the
power element plunger. If the nylon bearings are
worn or cause binding, replace them. Remove the
shutters and pulloutthe actuating arm (stub) shafts.
Push out the old bearings and push in new bearings
from the inside
of the shutter housing. The larger
bearingsurfaceactsas aspacer bushingandmustbe
on the inside of the housing.
TTERS
LOWER SHUTTER
ACTUATING ROD
ADJUST THE VERNATHERM
POWER ELEMENT TO REST
ON THE ROLLPIN WITH
SHUTTER CLOSED AT
AMBIENT TEMPERATURE
VERNATHERM BRACKET
ADJUSTING AND MOUNTING
SCREWS IN SLOTTED HOLES
FIGURE 11. AIR SHUTTER ADJUSTMENTS
17
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