Onan NH Instruction Manual

OPERATOR'SMANUAT
AND
PARTS
CATALOG ETECTRIC
GENERATING
PTANTS
FOR RECREATIONAL
SERTES NH
vEHrctEs
0 NAN' 14ooz3
R
D
AvEN
u
En..=;,,,r,,,1f.,
*L:*rf,':"r, MIruN
EsorA
8s432
940-310 6A.D72

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!
lilIn0DUCIt0ll
THISOPERATOR'SMAI{UAL
CONTAINS
IT{FORMATION
PERTAINING
TOTHEINSTALLATION,OPERATION,AND
MAINTENANCEOFYOUR
ONANUNIT. A PARTSCATALOGISALSO INCLUDED
IT{THIS
MANUAL.
t{E SUGGESTTHATTHIS MANUALANDTHEWIRINGDIAGRAMITHICH
ACCOMPANIESEVERYONAi{UNITBERETAINED
ANDREFERRED
TOWHENMAKING EOUIPMENT
ADJUSTMENTS
OR
ORDERINGPARTS.
ADDITIONALCOPIES
AREAVAILABLEFOR
A NOMINAL CHARGE
FROM
YOURONANDISTRIBUTOR,
WHENORDERING
PARTSREMEMBERTO INCLUDETHE ONAN
MODEL,SPECIFICATION
LETTER,
AND
SERIALNUMBER
LOCATED
ONTHENAMEPLATEOFYOURONAT{UNIT,THISISESSENTIALTO
ENSURETHECORRECTPARTIS
SHIPPED
TOYOU.
FORMAJORREPAIRSERVICE,CONTACTYOURONANAUTHORIZED
DISTRIBUTOR.

-
TABTEOFCONTENTS
TITLE PAGE
GeneralInformation..,. ...... 3
Specificatiols 5
Dime[sionsandClearances ,,.,,., 6
ools... 8
Installation
Operation
Adjustments
ServiceandMaintenance.
Parts Catalog
AssemblyTorquesandSpecialT
EngineTroubleshooting
Guide
LISTOFILLUSTRATIONS
Typical MobileInstallation
OnanVibration Isolators .
Battery andCround
Connection . . . . .
Load Connections
RemoteStart-Stop
Switch
Solid-StateControlBoard
Ignition Timing andBreaker
Points . .
Carburetor
Adjustments
Zenith Carburetor
Float Adjustrnent
SissionChoke
GovernorAdjustments
TappetAdjustment
Oil PressureRelief Valve Adjustment
Oil Level Indicator
Oil Filter
Air Cleaner
CrankcaseBreather .
Spatk
Plug Gap
CeneratorBrushes .
VacuumSpeed
Booster ,
Governor
BalI Joints
Fuel Filter
9
10
15
t7
22
26
Figure 1.
Figure 2.
Figure 3.
Figure 4.
Figure 5.
Figure 6.
Figure 7.
Figure 8.
Figure 9.
Figute 10.
Figure
11.
Figure 12.
Figure 13.
Figure 14,
Figure 15,
Figure 16.
Figure 17.
Figure 18.
Figure 19,
Figure20.
Figure
21.
Figure 22.
PAGE
10
lt
12
1J
13
t4
t7
18
18
19
l9
2l
2l
22.
23
23
23
24
ZJ
25

I
GENERAL
INFORMATION
INTRODUCTION
This manualincludes iflstructions for the installation,
operation, and maintenanceof the NH electric ge[er-
ating plants used in recreational vehicles. Identify
your model by referring to the MODEL AND SPECIFI-
CATION NUMBER as shown on the Onan nameolate.
Electrical characteristics are shown on the iower
portion of the nameplate.
How to interplet the MODEL and
SPECNO.
/ 12000
D
-T-r
Indicates KW
rating.
Factory codefor Seriesidentification.
Combines
with 1 and2 to indicate model.
3 - 120/240 voltage.
C - Indicates reconnectiblefeature.
R - REMOTE. Electric starti[g at the set or froma
remote location.
4, Factoty code for optional equipmentaddedto unit,
5. Specification (Spec) letter. Advanceswher factoly
makes production modifications.
Onanelectric plants are give[ a completerunningtest
urder various load conditionsandare thoroughlycheck-
ed before leaving the factory. Upor receipt of yout unit
check it thoroughly for any damage that rnay have
occurred during shippiflg. Tighten loose parts, teplace
missing parts, and repair any damagebefore putting
the unit into oDelation.
3CR
---'t-
I
NH
T
2
5.5
T
I
1.
2.
3.
iIANT
TACTIRTR'S
W{RR{IITY
ot vt R(:lr
r\Trrrr.rTr { r,{tl(rr\r

!
BREAKER POINT
BOX
SOLID STATE CONTROL
AIFI CLEANER
SISS
ON
CHOKE
TIMING
ACCESS hOLE
.-AC OUTPUT BOX
ANO PLANT GROUND
TERMINAL
VACUUM SPEE
BOOSTER GENERATOR
o cooLtNG
0\2
START S
OLENOID
ELECTRIC
FUEL PUMP
IBRATION 15
OLATOR
IL DRAIN
TYPICAL
NH
FOR
RECREATIONAL
VEHICLES
4

!
SPECIFICATIONS
C
ylinder Bore (inches),
Number
of Cylinders
ENGINE
llorsepower
Maximum
Minimum
CubicInch D
isplacement.
5.5
NH
14.0
bhp
@
1800
RPM
2
60
3-9/t6
3
7.0
to1
1800
Battery
12
Volt
One
74amp/ht.
Two-Step
6amp.
1.5
amp.
Excite!
Cranking
Regular
Grade
withFilter Change)
5%(3Hettz)
65
00
27.1+
1.0
JJ
20-13
/16 "
1l -1/) "
350lbs.
Piston Stroke(inches)
Compression
Ratio
RPM(60
Hertz)
Battery Voltage
BatterySize
SAEGroup
60
SAERating - 20 Hour
(nominal)
BatteryChargeRate
StaftirlgSystem
Oil Capacity(Quarts) . . 4.0 (4.5
Fuel
GENERATOR
ACVoltageRegulation.
ACFrequencyRegulation
(No
Load
toRated
Load)
60HertzRecreational Vehicle Rating(watts)
Cunent Rating (amperes)
Phase
PowerFactor
sETDI
Length MENSIONS
(Approximore)
width
Height
Weight
NOTE: Hertz is a unit of frequency equalto onecycle persecond,
+ Reconnectibleto deliverratedoutput
at 120 volt, 2
wite (54.2amp);
240volt, 2wite (27.1
amp).

!
DI'NENSIONS
AND CTEARANCES
ALL
CLEARANCESGIVENAT
All dinensions ininches
V
alve TappetClearance
ln
lake
.
Exhaust
.
Valve Stemin Guide
- Intake
Valve
Stem
in Guide
- Exhaust
Valve Spring
Length
Free
Lenglh.
C
ompressed
Lenglh
.
ValveSpringTension(lb.
)
Open
C
losed
Valve SeatBore Diametet
lnl ake.
Exhaust.
Va1veSeat Diameter
lnt
ake
,
Exhausl
.
Val i,e Slem Diameter
Intake.
Exhaust
Valre Guide
Drameter
(1.D.)
Valve Lifter Diameter
Valve Lifter Bore
Valve Seat lnlcrference
liidlh
Valve FaceAngle
Valve Seat Angle
Valve Interference Ang
Ie.
Cranksha! Main Bearing.
Crankshaft ti nd Play
CamshaflBearing
Camshafl lind Play
( umshaftLrft
Camshaft Bc.rring Diameter
Camshalt J ournal Diameter
I?od Beari ng (Forged Rod)
Connecting
Rod End Play (Ductile lron).
'I'i
miog Gear
Backlash
Oil Pump
GearBacklash.
I)is1on
to Cylinder, StrutType (Measured
below oil-controlling ring -
90 frompin) Clearance
l)iston Pio [)iameter
Pi
ston Pin in Piston.
Pist on Pin in Rod
Piston Ring Groove
Width
Top
l.
Top2.
Top3.
Piston Ring Gap in Cylinder.
Piston Ring Side Clearance(Top compression
ring only)
Breaker Point Gap (Full Separation).
SparkPlug Gap - For Gasoline
Fuel
ROOMTEMPERATURE
OF
70"F
unless olherwise soeci{ied. Minimum Moximum
0.003
*
7l
38
0.0010
0.0025
1.5645
1
.2510
1.569
0.3125
0.3410
0.344
0.7475
0.7505
r/32
0.002s
0.005
0.0015
0.003
1.3760
1.3740
0.0005
0.002
0.002
0.002
0.0015
0.75
00
0.0001
0.0955
0.0955
0.1880
0.010 0.006
0.020
0.025
0.010+ 0.0025
0.0M0
1.662
1.375
79
42
1.5655
1.2s20
1.570
t.256
0.343
0
0.3415
0.346
0.7480
0.7s
15
3/64
44"
45"
0.0038
0.009
0.003
0
0.033 1.3770
r.3745
0.0023
0.016
0.003
0.005
0.0035
0.7502
ThumbPush
Fi t
0.0005
0.0965
0.0965
0.1890
0.020

!
Crankshaft
Main
Bearing
Journal
- StandardSize
Main
Beari
ng
D
iameter
.
Main
BearingClearance
Crankshaft
Rod Bearing
Joumal - StandardSize
Cylinder
Bore
- StandardSize.
Ignition Tirning(Without
AutomaticSparkAdvance)
Stopped(Vith Automatic SparkAdvance)
Running
(WithAutomaticSpark
Advance).
Magneto
Pole ShoeAir Gap
*1.001
"
t.9992
2.0015
0.0015
t.6 2
22"BTC
3
OATC
22"B"tC
0.010
2.0000
2.0M0
0.0043
r.6260
3.5
635
0.015

!
ASSETNBTY
TORQUES
AND SPECIAT
TOOTS
TORQUE
Assembly torques as given here require the use of a
torque wrench. These assembly torques will assure
propertightness without danger of strippingthe threads.
If a torque lvrench is not available, you will have to
estimate the degreeof tightness necessary
for the stud,
nut or screw being installed andtighten accordingly.
Be
careful not to strip the threads. Check all studs, nuts
and screws often with the engine cold. Tighten as
needed to prevent them frorn working loose.
Special Place Bolts do not require lockwashers or
gaskets. Never attempt to use a lockwasher with these
bolts, it will defeattheir purpose.Check all studs, nuts
and screws often. Tighten as needed.
R€C
ESS
UNDER
HEAD
TOROUE
SPECIFICATIONSINLB-FT
SPECIAL
TOOLS
These tools are available fromOnan
to aid
repairwork.
Crankshaft
GearPullingRing.... .....
MainCrankshaft
Bearing
Driver
Frontand
Rear
.
Camshaft
Bearing
Driver
Ftont..
Rear
Valve Seat
Driver .
Valve SeatStaker
Intake.
. .
Exhaust
serviceand
. 420A248
. 420867
. 420A66
. 420A307
. 4204308
. 420A3 09
. 420A310
. 4208311
. 4 208181
. 420A314
. 420A315
Valve SeatCutter .
Oil Seal Guide
andDriver. . . .
Camshaft
Bearing
Remover . .
Crankshaft
BearingRemover. . .
Connecting Rod Bolt
FlywheelMountingsctew..........
F ur-l
Pump[lounting Screws
Oil Pump
Ccarcase
Cover
Ii(.arBeaong
PIate ..
Oil Base l\4odnl
Ing Screws.
CylinderHeadBolt....
SparkPlugs.
Valve Cover N ut .
Manifold Screws - lotake and Exhaust . .
Magneto
Stator
Screws . .
Carbureror Moun ting Stud Nuts
ArmatureThrough
Stud
Nur ,
GeneratorThroughStud
Nut.. .. .....
Blower Housrn
g Screws
Generator Adapter - To Cylindet Block . . .
Starter
Bracket - To Oil Base
>
'/e-4
Min. Max.
27 29
35 40
56
79
8 10
25 27
18 23
17 19
15 20
48
16 23
8 10
812
35 40
74 16
10 15
15 18
43 48

t
ENGINE
TROUBTESHOOTING
GASOLIN
E
ENGIN
E
TROUBTE5HOOTING
GUIDE
CAUSE

!
INSTATTATION
If the electric generatingplant is to operate properly, it
must be correctly installed. This manual gives some
of the moreimportant aspects of installatio[. For more
details, a Technical Bulletin (T-012) is available frorn
Onan.
Ventilatiort is the most importantfactor to consider.The
unit musthave enoughcooling air to operate safely and
efficiently. The heatedair mustbe disposedof to keep
the engine frorn
overheating
and losing power. For the
NH plalt tunning at 1800tpm, the amount of air dis-
charged is 750cfm. The minimum free air inlet with no
filter or restriction is 140 sq. in.
Onan Vacu-Flo cooled units are specifically designed
for mounting in small compartments (where proper
cooling is difficult) and are equipped to provide suf-
ficient cooling air and adequate disposition of heated
air. With this type of cooling, a centrifugal fan in a
scroll housing pulls cooling air into the compartment
PROVIOE OPENINGS IN
OOOR FOR ENTRAN CE
AND COOLING AIR ANO
HEATED AIR
COMPARTMENT
OF COMBUSTION
FOR ESCAPE OF
oAo wtR
TYPE
FUEL LIN
PIPE EXHAUST TO
PERIMETER OF VE HICLE
FIGURE
I. TYPICALMOBILEINSTALLATION
10

t
and over the cooling fins and surfaces of the eneine.
Heated air is expelled through a single discharge and
away from the unit and installatton area.
LOCATION
The compartment
itself shouldbe of vapor tight design
and completely independent of living quarters. The
interior Iining should
be fireproof.A sheet metalcover-
ed compartment
may be readily sealed and lends itself
easily to treatment.The set may have to be removed
fot service, so nrakethe door large enough
to facilitate
removalof the unit,
The compartment
location is determinedby physical
size, accessopeningand mostimportalt, best mounting
support. Allow 2" clearance on a1l sides of the unit
for rocking on mounts.
POSITIONING
The following should be considered for accessibility
when mounting the unit in a compartment.
(Position
so operating instructions and nameplate are visible
and/or install an accessible nameplate. data decal
or sticker.
)
I. Make air discharge duct as short as possible.
Position so exhaust heated air is flot drawn into
cool air inlet.
2, Air cleaner shouldbe easy to lemove and service.
3. Battery or batteriesmust
be accessiblefor service.
4. Oil fill tube cap should be easy to reach.
5. The control box switch should be visible.
6. Provide space for muffler.
7. Oi1 drain should be readily accessible.
8. Cylindet head should be readily accessible for
servtce.
9. Rope stait sheaveshouldbe accessible.
MOUNTING
The best methodof mounting
is to attach the plant to a
.nountingplatfotm using Onan vibration isolators. See
Figure 2. The vibration isolators must be propetly in-
stalled to minirnizevibtation. The Onan mou[ts are a
"fail-safe" type with mountingbolts that prevent the
unit from breaking loose if the mounts are damaged.
The mountingbase should be fastened directly to the
supporting ftame. Channel, box or angle iron can be
used for a mountingbase ftame.This will provide the
greatest support, plus a base sealed against air, dirt
and sound.Do not use sheetmetalor thin Dlate
without
a supportingframe.
Plywood is vulnetable to climatic
elerrenls, will tend to become oil
s<>aked,and is not [ireprool.
The supportingbase or platformmust be strongenough
to withstand the shock from sharp turns, bumps,holes,
etc. which accompanymobile applications. Brace the
mounting
platform to eliminate any chance of the plat-
form bowing or bendin
g.
FIGURE
2. ONANVIERATION
ISOLATORS
FUEL SUPPLY (GASOLINE)
Install a separate
fuel tank for the unit. If the plant has
to be connected
to the vehicle supply tank, do not tee
off the vehicle supply line. The generatiflg
plant rnust
have a separate fuel line because the more powerful
vehicle fuel pump will starve the generatingunit for
gasoline.
FUEL LINES
Use annealed copper ot seamless steel tubing and
flated connections. Run fuel lines, at the top level
of the tank to a point as close to the engineas possible,
to reducethe dangeroI fuel siphoning out of the tank
if the line should
break.
Install lines so they are acces-
sible at all times ard protectedfrommechanicalinjury.
Use nonferrousmetal sttaps, without sharp edges, to
secure
the fuel lines.
EXHAUST
SYSTEM
Observe the following when installing the plant's ex-
haust system:
6.VIBRATION ISOLATOR
7-SPACER BUSHING
A-v\/ASHER
9-SCREW
_TO ALLOW UNIT
TO ROCK ON ITS
MOUNTS
..FAIL-SAFE''
11

I
2.
Construct exhaust system to prevent damage
from
leakage
andvibtation. Use automotivetype hangels
and connections under the vehicle.
Use an insulating thimble where exhaust piping
passes through a partition or floor of flammable
rnaterial. Exhaust lines may be asbestos wrapped
to reduce heat radiation within the compadment.
Terminate the exhaust outlet aft of the set com-
partment and extend to perimeter of vehicle so
DEADLY exhaust fumes will not enter vehicle
undet ordinary conditions of driving or parking.
lasoline Iiller
Vacu-Flo sctoll.
Do not install the exhaustoutlet
closer than three feet lrom the
spout- Do not pipe exhaust into
When installing mufflers, other than those supplied
with the unit or if the exhaust system is excessively
complicated, the exhaust back pressure should be
checked.
Exhaustback pressure
at ratedload, measured
at the exhaust manifold, should not exceed 2 in. Hg.
(Mercurycolurnn).
Where
a tappedhole is not provided,
the manifold and/or a pipe couplingmay be drilled and
tapped.After measurement
is made,
plug the hole with
an ordinarypipe plug.
BATTERY
CONNECTION
Connect the positive (+) battery cable to the start
solenoid. Connect
the negative(-) cable to the gener-
ator th.ough-bolt.Refer to Figure 3.
Do notdisconnect
the sta inEballeries
while the engine is runninp. The
.esultirg overvoltage will danage the electric choke
and other control components. Do not revetse battery
connections; doinS so ney damagethe eleclrical sysfem.
In mobile applications where
the generator
is notmally
operated in ambient temperaturesabove OoF and the
battery is kept charged
by frequentrunningof the unit,
a single 12volt battery of 74
amp/ht capacity minimum
is sufficient.
GROUND
(GENERATOR
TO VEHICLE)
A solderless terminal is provided between AC output
box and control on top side of unit. Connect a ground
between
this terminal and clean, bare metal on vehicle
frame. SeeFigure3.
LOAD WIRE
CONNECTIONS
The set nameplateshows the electrical output rating
of the set in watts, volts and c5rcles. The wiring
diagramshows the electrical circuits and connections
necessary for the available output voltage. Also see
Fi
eure
4.
1.
3.
I rarNiirc | ?'
-lor
monoxide ot other
not use discha.ged Vacu-F lo at
heatin! since it may contain carbon
poisonous dases.
€ROUNDIN6 LUO
/OROUND PLA,rt TO CLEAN,BARE
/ A.sRouNo oN .=HtcLE FRAME
-_-l
FIGURE
3. BATTERY
AND
GROUNOCONNECTION
L2

!
120 VOLT, 2 W|RE
UNGROUNDED LOAD WIRE ^ M1, M3
T,"-"',
I (BLACK)
I
120 V.(Full nameplate rating)
240 VOLT, 2 W|RE
UNGROUNDED LOAD \^/IRE
+M3 (BLACK]
a
o
IJJ
)
c
ul
z
uJ
o
U'
o
J
E.
f-
E.
ul
z
o
240 V. nameplare rating) | r,ar.r,,ll
(JOIN)
GROUNDED LOAD
(w HrTE) M'2. M4
(JOIN AND
6ROUND)
GROUNDEp LOAp W|RE I M2
(wHtTE)
NOTE: On
ly halt nameplat€
rating can be taken oft each
120 volt connsction.
'r20l240
voLT. 3 WtRE
UNGROUNDED LOAD WIRE (ALACK)
FIGURE
4. LOAD
CONN
ECTIONS
M2, M3 (JO|N)
120 V.
Meet all applicable code requirements. A qualified
serviceman
or electlician should oake the installation
and the installation should e inspected and approved.
The AC output box has provisions
to accommodate
load
wires. Use flexible conduit and stranded load wires
near the set io absorb vibtation. Use sufficiently large
insulated u'ires. Strip the insulation from the wire ends
as necessary for clean connections. Connect each load
u'ire to the proper geneEtor output lead inside the AC
outpd box. Insulate bare ends of ungroundedwires.
Install a fused main switch (or circuit breaker)
between
the generatingset and the load.
Output Leod Morkings: Generatorleads are marked,
M1,M2,M3 and
Mq.
These identifying marksalso appear
on the wiring diagram.
Yoltoge Selection on ReconnectibleSingle Phose
Generqlors:These units are reconnectible for use as
120/240volt, 3wire; 120volt, 2wire; or a 240volt,
2wire powersource(see Figure 4). Use the connection
for two wire service vrhenone load exceeds 1/2 the
rated capacity. Balance the load when condectiflg
for
three-wireservice.
Boloncing the Lood: Current for any one output lead
ftust not exceed nameplate rating. Serious
overloading
can damagethe generator
windings. Whentwo ot more
single phase circuits are available, divide the load
equally betweenthem.
CONTROL
BOARDREMOTE
WIRING
(BEGIN
SPECR)
The printed circuit board (located uder start-stop
control) is the "heart" of the generating
plart's control
system. Terminals 1 through 9, on the left side of
printed circuit board, @igure 6) connect to engine
componentssuch as:
. Ignition Points
a Ignitioq Coil andFuel Purnp
a StartSolenoid
. LOP (Low Oil Pressure)
. HET (HiCh
EngineTemperatule)
r Charging
Resistors
Terminals10through18, located
onright side of printed
citcuit boatd, aie for connectionto a Remote Control
Station.
These includethe following options:
. Stalt-Stop
Switch
a Charging
Arnrneter
a Running
Time Meter
a Generator
,,On', Light
a LOP (Low Oil Pressure) Alarrn
. HET (HiChEngine Ternperature)
Alarm
PRINTEO CIRCUIT AOARO
CONNECTION TERMINAIS @
@
o
TERMINALS 13 ANO 14 MUSA
EE CONNECTEO TO ONE SIDE
TERMINALS 15 ANO 16 MUST
BE CONNECTED TO OTHER
INTEFICHAN6ING THESE CON
N€CTIONS WILL OAMAGE
PRINIED C'RCUIT BOARD
,a'
OOUBLE PO!E OOUBLE THROv/
REMOTE START.STOP SWITCH
UNGROUNDED LOAD WIRE (B LACK)
13
FIGURE
5. REMOTE
START.STOP
SWITCH

!
RemoieStort-StopSwitch:To connecta remote
start-
stop switch, use a double-throw, double-pole switch
(Onan
No.308A329)
and connectas shownin Figures
5 and6. Use
No. 18wires for connection
for distances
up to 250 feet.
f.ffi6l-l 1-,rnin.t.lI.t.is a troun.rl
.onni\tion [ol
/.-,-__v** _( lh, Itrlnl.,l , trt tttl bu trd ,tntl musl
a1*a1s 60 1'()nnr'(-'t0d.
}---'-'-.-y D., n,,r .,tt.mnt t,,, h,,.k tor , wr,.nl fluw
t-9ly19lJ 'at ttt prirtri
,t ' it,uit b,,.trJb11ump,r'
ingi across componenls with a sctewdriver, wite, etc'
Always have lhese boards checked by an authotized
Onan Service Center or a qualilied electrician usin!
the ptopet instrufients (e.9,. voltmetet, ohmtueter ot
multlmetet),
Fused Conneclion: A small fuse (Ft), used to protecl
the circuit in case battery con[ections are revetsed, is
located under the Stop side of Slart-Stop switch (be-
tween CR4 and CRS). If fuse is damaged, replace by
carefully clearing out solder holes and replacing thc'
fuse with a bare, No. 36 wire and resoldering the holes.
1a
17
't6
't5
AMMETER_
AMMETER +
START SOL. 9START SW
START SW
A OHM RES
4 OHM RES 7
SEEFIGUR
E 5
corL &
FUEL PU
MP
BATTERY
LOP
HET
A1
IGN POINTS
6
514 STOP
13 6ND &
12 LOP
11 HET
sw
STOP S
4
3
2
1
10 GEN ON LIGHT
RUNNING TIME METER
FI FUSE
L--------
na
FIGURE
6. SOLID-STATE CONTROL
SOARD
t4

!
OPERATION
BEFORE
STARTING
Cronkcose Oil: Be sure the crankcase has been filled
with oil to the "FULL" markon the oil level indicator.
Refer to the MAINTENANCE SECTION for the recom-
mended oil changes and cornplete lubricating oil re-
commendations.
Recomnended Fuel: Use clean, fresh, regular grade,
automotivegasoline. Do not use highly leaded
prernium
tjrpes.
Fot new engines, the most satisfactory results are
obtained
by usingnonleaded
gasoline.For olderengines
that have previously used leadedgasoline, heads
must
be taken off and all lead deposits removedfromengine
before switching to nonleadedgasoline.
1. Onehalf hourat 1/2 load.
2. Oaehalf houtat 3/4 load.
3. Full load.
4. Change crankcase oil afte! the first 50 hours of
operatton.
BATTERY CHARGING
(Beein
SpecD)
The batterychargerate is automaticallycontrolled by a
solid-state voltage regulator.
The high chargetate was
set at the factory for average operating conditions.
INFREQUENTSERYICE
If the unit is used infrequently, extended shutdown
periods can result in difficult starting. Run unit at
least 30 minutescvery week to elirninate
hard startitrg.
HIGHTEMPERATURES
1. See
that nothingobstfucts air flow to and ftom the
plant.
2, Keep cooling fins clean. Air housing should be
ptoperly installed and undamaged-
3. Keep ignition timi[g properlyadjusted.
LOW
TEMPERATURES
1. Use coftect SAE No. oil for temperature
conditioos.
Change
oil only when eogine is warm, lf an unex-
pected
temperaturedrop
causesan emergency,
move
the vehicle to a warm location.
2. Use fresh gasoline. Protect against moistule
condensation, Below 0oF adjust carburetor main
jet for a slightly richer fuel mixture.
3, Keep ignition system clean, properly adjusted and
batteriesin a well chatged
condition,
4. Partially restrict cool air flow, but use care to
avoid ovelheating,
OUT.OF.SERVICE
PROTECTION
Protect a plant that will be out-of-servicefor morethan
30 days as follows:
1. Run the plant until thoroughlywarm,
2. Turn ofl fuel supply and run until engine stops.
3. Drain oil fromoil base while still warn. Refill and
attach a warning tag stating oil viscosity used.
4. Remove each spark plug. Pour 1 oz. (two table-
spoons)
of rust inhibitor (or SAE #50oil) into each
cylinder. Crank engine slowly (by hand) several
times. Install spark plugs.
5. Service air cleaner.
6. Clean governor linkage and protect by wrapping
with a clean cloth.
7. Plug exhaust
outlet to prevent entrance
of moisture,
dirt,
bugs,etc.
8. Wipe genetatot brushes, slip rilgs, etc. Do not
apply lubricant or preservative.
II lead deposits ate nol
enpine betote switching
nonlea<lecl pasoline, geignitioa could
seyerc diilk?Ele
to the engine.
ELECTRIC STARTING
Push the Start-Stopswitch to its .,START,, position.
Release the switch as soonas the eoginestarts.
If the enginefails to sta.t at first try, inhibitor oil used
at the factory mayhave fouledthe sparkplugs. Remove
the plugs, clean in a suitable solvent, dry thoroughly
and install. Heavy exhaust smoke when the engirieis
first started is norhal and is caused bv the inhibitor
oil.
APPLYING LOAD
If practical, allow u[it to warm up beforeconnecting
a heavy load. Continuous generatoroverloading may
cause high operating temperatures
that can damage
the
windings. Keep the load within the nameplaterating.
STOPPING
1. Push Start-Stopswitch to "STOP', position.
2. Releaseswitch when
unit stoDS.
BREAK.INPROCEDUR
E
Controlledbreak-inwith the properoil and a conscien-
tiously applied maintenance ptogram
will helpto assure
satisfactory service fromyour Onanelectric generating
plant.
When
operatingenginefor the first time, usethe fo1low-
ing sequence
using SE or SE/CC oil (former designation
was
MSorMS/DG):
temoved ftom
Itom leaded to
occtn causinli

!
9. Wipe entire unit. Coat rustable parts with a light
film of grease or oil.
10. If battery is used, disconoect and follow standard
battery storage procedure.
DUST AND DIRT
l. Keep plant clean. Keep cooling surfaces clean.
2. Service air cleaner as frequently as necessary.
3. Change crankcase oil every 50 operating hours
or sooncr.
4. Kcep oil and gasoline in dust-tight containers.
5. Keep governor linkage clean.
6. Clean generator btushes, slip rings and commutatot.
Do nol remove normal (dark btown) film. Do oot
pol
ish.
HIGH
ALTITUDE
For operation
at altitudes of 2500feet abovesea level,
close carburetormain jet adjustmentslightly to main-
tain properair-to-fuel ratio (refet to the ADJUSTMENT
SECTION),Maximum
powerwill be reducedapproxi-
mately4%for each 1000feet abovesea level, after lhe
first 1000 feet.
SEQUENCEOF OP
ERATION
SeeTable 1 for a typical sequcnc{: of operationfor your
Onanelecttic generatingplant.
TABLE
I. SEQUENCE OFOPERATION
Operate
starlswrtch.
Energizes
statt so
Solenoid cofltacts close,
Battery currentfed to ignition
coil and
fuel pump. Currentfed to electlic
chokeoperates
carbuletor
choke.
Current
fedto generator
seriesfield, cranks
englne.
Operate
start switch until ge$eiatorspeed
builds up.
Generator
DC cunent produced. AC output current ptoduced
and fed to load.
Release
start switch.
Recharges
baltery.
Takes over energizing of trarlsistorized
start disconnect.
The charge rate is high when the battery is not fully
charged. DC current passes tluough both the resistor
and transistor which are paralleled by operation of
transistorized circuitry.
Whenthe battery
becomcs
fully charged,the solid
state voltage regulatorremovcs
a resistor ftom the
circuit and current passes through the low rate
tesrslor only.
!
l6

I
ADJUSTTIENTS
GEN
ERAL
Satisfactory engine performance is largely dependent
upon corect adjustments. However, adjustments can-
not fully compensate
for low enginepowet due to wear,
etc. If ttouble develops, follow an orderly procedure
to determinethe cause before making any adjustment.
Refer to the Troubleshooting
Chart for help in checking
causes of troubles which may occur,
BREAKER
POINTS
1. Remove the two screws and the cover on the
breakerbox.
2. Remove the two spark plugs so engine can be
easily rotated by hand.
3. Turn flywheel in a clockwise direction approxi-
mately 1/4 turn after top center (TC).
4. To adjust gap refer to Figure 7, Loosen screws
(A) and turn cam (B) until point gap measures
.020
" with a flat thickness gauge. Retighten
screws (A) and recheck gap.
5. If points are slightly butned, dress smoothwith a
file or fine stone. If points appearto be burned
and pitted, replacethem with a new set.
6. Replace spark plugs and breakerbox cover.
IGNITIONTIMING
Both spark plugs on the NH fire simultaneously,thus
the needfor a distributor is eliminated. Sparkadvance
is set at 22oBTC (before top center) and should be
maintainedfor best engine performance.Always check
timing after replacing ignition points or if noticrog
poot engine performance.
Ptoceedas follows:
Timing Procedure
- Engine
Running:
1. To accurately check the ignition timing, use a
tirning light when engine is running. Connect the
timing light accotding to its manufacturer's in-
structions. Either spark plug calr be used as they
fite simultaneously.
2. Removethe plug from the timing hole.
3. Start the engine and check the timing. The mark
on the fllnvheel should line up with the 22oBTC
mark on the cover.
4. If timing oeeds adjustment, loosen the mourting
screws on breaker box arrd
move left to retard or
right to advance the timing.
5. Start engineto be sure mark on fltmheel lines up
wfth 22o markon cover.
6. Tighten all screws, replace tirning plug,
TimingProcedure
- Engine
NotRunning:
1. Connect a continuity test lamp set acrcss the
ignition breaker points. Touch one test prod to
the breakerbox terminalto which the coil lead is
connectedand touch the other test piod to a good
ground or! the engine.
2. Turn crankshaftagainstrotation
(counterclockwise)
until the points close. Then slowly turn the crank'
shaft with rotation (clockwise).
3. The lamp should go out just as the points break
which is the time at which ignition occurs (22"
BTC).
I
I
t
I
MAFIK ON FLYW HEEL
FOR MODELS WITH
BREAKER BOX FACING
FRONT OF ENGINE
ADVANCE SPARK ..>
OF <- RETARD SPARK
--1 PLACE A DROP
LIGHT OILON
N TIMING MARKS BRE,AKER ARM PIVOT
SHAFT EVERY ,I2OO
OPERATING HOURS
ll
ll
tl
it
ii
il ..,,
rr:_'_
TO ADJUST OAP
LOOSEN SCREWS
TURN CAM @
SET BREAKER
GAP WIOTH ATPOI
o.o20"
LOOSEN THESE
SCREWS TO ADJUST
_)
POSITION OF
BREAKER BOX
REFERENCE
MARK
FIGURE
7. IGNITIONTIMING AND
BREAKER
POINTS . d
T7

!
CARBURETOR
ADJUsTMENT
The carburetor(Figuie 8) has a high speed fuel main
adjustment (needle A) and a fuel idle adjustment
(needle B).
Adjust the calburetor to obtain the corfect fuel-to-air
mixture for smooth, efficient operation.The carburetor
should be adjusted in two steps - first the load adjust-
ment and then the idle adjustment.
IMPORTANT; II the carburetot is completely out ol
adjustment so tfie enlline will not tun, open both needle
valves 1 to 1-1/2 tutns otl their seats
to permit starting.
Do not force the needle yalyes a{ainsf tleir seats. Tfiis
will bend the needle.
Before adjusting the carburetor,be sure the ignition
s],stem
is workingproperly
and
the governor
is adjusted.
Then allow the engineto warmup.
1. With no load, turn the idle adjustment out until
the engine speed drops slightly below normal.
Then turn the needle in until the engine speed
retums to normal.
2. Apply a full load to the ergine.
3. Carefully turn the main adjustmeot
in until speed
drops slightly below normal.Then turn needleout
until speedreturns to normal.
THROTTL
E
STOP
SCRE
THIS
OISTANCE
t/32" AT NOLOAO
MAIN
FUEL
AOJUSTTIE
NT
YLO ROOEXTENDIXG
DOWXTHROUGHLOIVER
SHROUOPAN
FIGURE
8. CARBURETOR ADJ
USTM
ENTS
Alternote
Method:Use When
Thereis No Lood Adiust-
rnent
Pos
sible.
1. Start the engineand allow it to warm
up.
2. Push in on the governormechanismto slow the
unit down to about800-900rpm.
3. Set the idle adjustrnedtscrew for even operation
(so the engine is running smoothly).
4. Release the governor mechanism to allow the
engifle to accelerate. If the engine accelerates
evenly and without a lag, the main adjustment
is correct. If not, adjust the needleoutward about
l/2 tltn and again slow down the engine and
release the rnechanism.
Continue until the ensine
accelerates evenly and without a tirne lag after
releasing the governor.
With the carburetor and governor adjusted, set the
throttle stop screw, Figure 8, to allow 1/32 inch clear-
ance to the stop pin with the engine operating at no
load, This prevents excessive hunting when a large
Ioad is suddenly
removed.
To check float level, femove
the entire mainfuel adjust-
ment assembly ftom the float bowl (unscrew large nut
fromthe floatbowl).The properdistance ftom the float
to the carburetor
bodyis 1/8 inch, The float tab should
just touch the fuel inlet valve. Adjust by bending the
tab on the float. See
Fieure 9.
SI{OULD
BE
A9rr |/a"
FIGURE
9. ZENITH
CARSURETOR
FLOAT AOJUSTMENT
stssoN
cHoKE
This choke uses a heat sensitive bimetal element to
control the choke plate position. In addition to this,
a solenoid is actuatedduting engine cranking, closing
the choke all the way. The bimetal is factory set to
position the choke to the proper opening under any
ambientcondition,
If adjustment of the bimetal is needed, it must be made
at ambient temperature.Do oot attempt adjustments
until engine has been shut downfor at least one hour.
Loosen the screw which secures the choke actuating
arm to the linkage. Refer to Figure 10. Shorteningthe
actuating armmakesthe fuel mixture richer. Lengthen-
ing the arrnmakes the fuel mixture lean. For ambient
temperatufesabove 85"F, the choke should be fully
opened. For ambient temperatures
below 25"F, the
choke should be opened l/4 inch with the solenoid
not engaged.
Tighten the screw that secures
the choke
actuating aim to the linkage.
18