Generac Power Systems NP-50G Series User manual

Manual No. A6448
Air-cooled Recreational
Vehicle Generator
OWNER'S MANUAL
POWER SYSTEMS INC.
Model No. 00916*1 Series NP-50G
THIS SYMBOL POINTS OUT IMPORTANT SAFETY INSTRUCTIONS. WHICH. IF NOT FOLLOWED. COULD ENDANGER THE
PERSONAL SAFETY AND OR PROPERTY OF YOURSELF AND OTHERS. READ AND FOLLOW ALL INSTRUCTIONS IN THE
MANUAL BEFORE ATTEMPTING TO OPERATE THIS UNIT.
Revision 1 (8/6/98)
Printed in U.S.A.

- T HE MANUFACTURER SUGGESTS THAT THESE “RULES” FOR SAFE OPERATION BE COPIED AND POSTED
A IN POTENTIAL HAZARD AREAS OF THE RECREATIONAL VEHICLE. SAFETY SHOULD BE STRESSED TO ALL
”1 OPERATORS AND POTENTIAL OPERATORS OF THIS EQUIPMENT
• Inspect the generator periodically. Repair or replace all damaged or
defective parts immediately.
A In case of accident caused by electric shock, shut down the source
of electrical power at once. If this cannot be done, free victim from live
conductor. AVOID DIRECT CONTACT WITH THE VICTIM. Use a dry
board, dry rope, or other non-conducting implement to free the victim
from live conductor. If victim Is unconscious, apply first aid and get
medical help.
• Inspect fuel system frequently for leaks or damage. Repair or replace
any damaged or leaking component immediately. Never attempt to
change, alter or modify the generator fuel system in any way that might
affect safety or compliance with applicable codes and standards.
The engine exhaust from this product
contains chemicals known to the State
of California to cause cancer, birth
defects, or other reproductive harm.
Study these SAFETY RULES carefully before installing, operating or ser¬
vicing this equipment. Become familiar with the Owner’s Manual and with
the generator. The generator can operate safely, efficiently and reliably only
if it is properly installed, operated and maintained. Many accidents are
caused by failing to follow simple and fundamental rules or precautions.
Generac cannot possibly anticipate every possible circumstance that might
involve a hazard. The warnings in this Manual and on tags and decals affixed
to the unit are therefore, not all-indusive. If you use a procedure, work method
or operating technique Generac does not specifically recommend, you
must satisfy yourself that it is safe for you and others. You must also make
sure the procedure, work method or operating technique that you choose
does not render the generator to be unsafe.
• For fire safety, the generator must be installed and maintained properly.
Installation must always comply with applicable codes, standards, laws
and regulations. Adhere strictly to local, state and national electrical and
building codes. Comply with regulations the Occupational Safety and
Health Administration (OSHA) established. Also, the generator and
related components must be installed completely in conformance with
the manufacturer's instructions and recommendations. Following proper
A The generator engine gives off DEADLY carbon monoxide gas through
its exhaust system. This dangerous gas, if breathed in sufficient con¬
centrations, can cause unconsciousness or even death. This exhaust
system must have been properly installed, In strict compliance with
applicable codes and standards. Following installation, you must do
nothing that might render the system unsafe or in non-compliance with
such codes and standards. The generator compartment must be com¬
pletely vapor sealed from vehicle interior. There must be no possibility
of exhaust fumes entering the vehicle interior. Never operate this
equipment with a leaking or defective exhaust system.
• Never use the generator or any of its parts as a step. Stepping on the
installation, do nothing that might alter a safe installation and render the unit can stress and break parts and may result in dangerous operating
unit in non-compliance with such codes, standards, laws and regulations. conditions from leaking exhaust gases, fuel leakage, oil leakage, etc.
A The Recreational Vehicle Generator produces extremely high and
dangerous electrical voltages and can cause dangerous, and possi¬
bly fatal, electrical shock. Avoid contact with bare wires, terminals, etc.
while the unit is running. If you must work around an operating gen¬
erator, stand on an insulated, dry surface to reduce shock hazard.
Never work on this equipment or handle any electrical device while
standing in water, while barefoot, or while hands or feet are wet Dan¬
gerous electrical shock will result
• Have the generator properly grounded (bonded) during installation onto
the vehicle, either by solid mounting to the vehicle frame or chassis or
by means of an approved bonding conductor. DO NOT disconnect the
bonding conductor, if so equipped. DO NOT reconnect the bonding con¬
ductor to any generator part that might be removed or disassembled durtog
routine maintenance. If the grounding conductor must be replaced, use
only a flexible conductor that is of No. 8 AWG copper wire minimum.
• Keep hands, feet clothing, etc., away from drive belts, fans and other
moving parts of this equipment Never remove any drive belt or fan
guards while the unit is operating.
• Do not smoke around the generator. Wipe up any fuel, or oil spills imme¬
diately. Never leave oily or fuel soaked rags in the generator compartment
or on the generator itself. Keep the area around the generator clean and
free of debris.
• Adequate ventilation is required to expel toxic fumes and fuel vapors from
the generator compartment Do not alter the installation of this equip¬
ment in any manner that might obstruct air and ventilation openings. Such
openings must be kept dear and unobstructed.
Some generators may use LP gas (propane) as a fuel. LP gas is highly
EXPLOSIVE. The gas Is heavier than air and tends to settle in low
areas where even the slightest spark can ignite the gas and cause an
explosion.
• Before performing any maintenance on the generator set disconnect its
battery cables to prevent accidental start ip. Disconnect the cable from
the battery post indicated by a NEGATIVE, NEG or (-) first Reconnect
that cable last
Recreational Vehicle Generator

Generac NP-50G Recreational Vehicle Generator
TABLE
OF
CONTENTS
SAFETY RULES.Inside Front Cover
IDENTIFICATION RECORD.3
GENERAL FEATURES.3
READ THIS MANUAL THOROUGHLY
Operation and Maintenance.5
How to Obtain Service.5
GENERATOR FAMILIARIZATION
Generator Applicability.6
Installation.6
Safety. 6
Generator AC Connection System....;.6
OPERATION
Generator Control Panel.7
Optional Remote Start/Stop Panel.7
Automatic Choke.8
Before Starting the Engine.8
Starting the Generator.8-9
Stopping the Generator.9
Applying Loads to Generator.9
Summer/Winter Hear Riser System.9
Additional Information.10-12
SPECIFICATIONS
Fuel Requirements. 1 3
Engine Oil Requirements.13
Engine Specifications.13
Generator Specifications.....13
MAINTENANCE
Checking Engine Oil Level.14
Change Engine Oil.14
Change Oil Filter.14
Engine Air Cleaner. 1 5
Clean Air Intake Screen. 1 5
Engine Spark Plug... 1 5
Miscellaneous Maintenance.16-17
Out of Service Protection.17
Return the Unit to Service after Storage.17
TROUBLESHOOTING.18
ELECTRICAL DATA.19
REPAIR PARTS.20-29
EMISSIONS WARRANTY.30-31
BASIC 3-YEAR WARRANTY...back cover
Recreational Vehicle Generator

READ
THIS
Mi 1 UAL
Generac NP-50G Recreational Vehicle Generator
READ THIS MANUAL THOROUGHLY
If you don't understand any portion of this manual, contact Gen¬
erac for a demonstration of actual starting, operating and
servicing procedures.
Throughout this publication and on tags and decals affixed to
the generator, DANGER, WARNING, and CAUTION blocks are
used to alert you to special instructions about a particular oper¬
ation that may be hazardous if performed incorrectly or
carelessly. Observe them carefully.
These safety warnings cannot eliminate the hazards that they
indicate. Strict compliance with the special instructions while
performing the service plus “common sense" are major mea¬
sures to prevent accidents.
The following definitions apply to DANGER, WARNING, CAU¬
TION, and NOTE blocks found throughout the manual.
DANGER: Indicates an immediately hazardous sit¬
uation which, if not avoided, will result in death or
serious injury. Danger is limited to the most
extreme situations.
WARNING: Indicates a potentially hazardous situ¬
ation which, if not avoided, could result in death or
serious injury.
CAUTION: Indicates a potentially hazardous situa¬
tion which, if not avoided, may result in minor or
moderate injury. Caution may also be used to alert
against unsafe practices.
NOTE: After this heading you can read explanatory statements
that require special emphasis.
These symbols indicate the following:
Points out important safety information and, if not fol¬
lowed, could endanger personal safety and/or property
of yourself and others.
Potential fire hazard.
Potential electrical shock hazard.
The operator (driver) is responsible for proper and safe use
of the vehicle, equipment on the vehicle, and the safety of all
vehicle occupants. We strongly recommend that the opera¬
tor read this Owner’s Manual and thoroughly understand all
instructions before using this equipment. We also strongly rec¬
ommend instructing other occupants in the vehicle to properly
start and operate the generator. This prepares them if they
need to operate the equipment in an emergency.
OPERATION AND MAINTENANCE
It is the operator's responsibility to perform all safety checks;
to make sure that all maintenance for safe operation is per¬
formed promptly; and to have the equipment checked by an
Authorized Dealer periodically. Normal maintenance service
and replacement of parts are the responsibility of the
Owner/Operator and, as such, are not considered defects in
materials or workmanship within the terms of the warranty. Indi¬
vidual operating habits and usage contribute to the need for
maintenance service.
Proper maintenance and care of your recreational vehicle
generator assures a minimum number of problems and keeps
your operating expenses at a minimum. See your authorized
Dealer/Distributor for service aids and accessories.
HOW TO OBTAIN SERVICE
When your recreational vehicle generator requires servicing
or repairs, simply contact an Authorized Service Facility for
assistance. Service technicians are factory-trained and are
capable of handling all of your service needs.
When contacting an Authorized Service Facility or the factory
about parts and service, always supply the complete model
number and serial number of your unit as given on its data
decal.
The warranty on your generator is included in the Owner’s
Manual, as well as listings for repair parts.
DEALER LOCATOR PHONE NUMBER
To better assist our customers we have established a
Dealer Locator phone number which allows the customer
to call 24 hours a day to find the nearest Generac dealer.
This is just a dealer locator number, no technical service
can be provided on this line.
1 - 800 - 333-1322
Recreational Vehicle Generator

Generac NP-50G Recreational Vehicle Generator
GENERAL
INFORMATION
GENERATOR APPLICABILITY
These generators have been designed and manufactured for
supplying electrical power for recreational vehicles. You should
not modify the generator or use it for any application other than
for what it was designed. If there are any questions pertain¬
ing to its application, write or call the factory. Do not use the
unit until you have been advised by a competent authority.
DANGER: For fire safety, the generator must have
been properly installed in compliance with (1)
ANS1119.2-1975/NFPA 501C-1974 “Standard for
Recreational Vehicles, Part III, “Installation of Elec¬
trical Systems.” The generator also must have
been installed in strict compliance with the manu¬
facturer’s detailed installation instructions. After
installation, do nothing that might render the unit
in non-compliance with such codes, standards and
instructions.
An INSTALLATION MANUAL was shipped with the genera¬
tor. That manual contains manufacturer’s instructions and
recommendations for installing the unit into a recreational
vehicle. After installation, installers should forward the Instal¬
lation Manual to Owners/Operators for their information.
Owners/Operators have the responsibility to make sure that
nothing is done that might render the installation unsafe or in
non-compliance with applicable codes, standards and instruc¬
tions.
SAFETY
Before attempting to use the generator set, carefully read
GENERAL SAFETY RULES inside the cover of this Manual.
Comply strictly with these RULES to prevent accidents and
damage to equipment and/or property. We suggest that copy¬
ing and posting GENERAL SAFETY RULES in potential hazard
areas of the vehicle. Stress safety to all operators and poten¬
tial operators of this equipment.
You can use this generator to supply electrical power for oper¬
ating 120/240 volts, single phase, 60 Hertz, AC electrical
loads. These loads can require up to 4800 watts of (4.8kW)
of power, but cannot exceed 40 AC amperes of current at 120
volts or exceed 20 AC amperes at 240 volts.
CAUTION: Do not overload the generator. Some
installations may require that electrical loads be
alternated to avoid overloading. Applying exces¬
sively high electrical loads may damage the
generator and may shorten its life. Add up the
rated watts of all electrical lighting, appliance, tool
and motor loads the generator will power at one
time. This total should not be greater than the
wattage capacity of the generator. If an electrical
device nameplate gives only volts and amps, multi¬
ply volts times amps to obtain watts (volts x amps
= watts). Some electric motors require more watts
of power (or amps of current) for starting than for
continuous operation.
INSTALLATION
This Owner's Manual has been prepared under the assump¬
tion that a competent, qualified technician installed the
generator. We also assume the installer complied with all
applicable codes, standards and regulations pertaining to
installation.
GENERATOR AC CONNECTION
SYSTEM
This generator set is equipped with dual stator AC power
windings. These two stator windings supply electrical power
to customer electrical loads by means of a dual 2-wire con¬
nection system. Note, however, that neutral is grounded.
The generator may have been installed so that units power
120 volts AC loads (Figure 1); or you can wire them to con¬
nect both 120 and/or 240 volts AC electrical loads. Be sure
to install jumper wire between the circuit breakers when recon¬
necting for 120/240 volts. Refer to the Installation Manual for
more information.
Figure 1 — Connections for 120 Volts Only
Recreational Vehicle Generator

Generac NP-50G Recreational Vehicle Generator
GENERATOR CONTROL PANEL
Mounted on the generator control panel (Figure 2) are the fol¬
lowing features:
Figure 2 — Generator Control Panel
RJBB MAIN
START THA BRBAKBF)
■ FUEL PRIMER _
Before starting a cold engine (if it has not been started in more
than two weeks), you must press this switch for approximately
5 seconds to bring fuel from the tank to the carburetor. This
rocker type switch springs back into its original position when
you release it.
■ START/STOP SWITCH _
To crank and start the engine, hold this switch at its START
position. Release the switch when the engine starts. To stop
an operating engine, press and hold the switch in its STOP
position until the engine shuts off. The switch center position
is the RUN position.
■ FUSE _
Protects the engine DC control circuit against electrical over¬
load. If the fuse element has melted open due to overloading,
the engine cannot be cranked. If you must replace it, use only
an identical replacement fuse.
■ MAIN BREAKER _
Protects generators AC output circuit against overload and pro¬
vides a method of turning OFF the generators 120/240 volts
AC output to vehicle circuits. The NP-50G has one 20 amp
breaker and one 30 amp breaker.
NOTE: If the Series NP-50G has been reconnected for dual
voltage AC output (120/240 volts), you can install line break¬
ers having an amperage rating that is different than stated
above. The replacement line breakers consist of two sepa¬
rate breakers with a connecting piece between the breaker
handles (so that both breakers will operate at the same time).
If the unit is reconnected for dual voltage, it is no longer RVIA
listed.
OPTIONAL REMOTE
START/STOP PANEL
A remote mounted Start/Stop Panel is available, which allows
you to start and stop the generator engine conveniently from
inside the vehicle. Figure 3 shows the Model 9042 remote
panel which includes (a) start/stop switch and (b) a genera¬
tor run lamp.
Figure 3 — Optional Remote Panel (Model 9042)
r
v_ j
You can also order model 9043, a remote panel which includes
the (a start/stop switch, (b) the generator run lamp and (c) and
hourmeter. The hourmeter provides a continuous indication
of engine-generator operating time. Use the hourmeter for
checking off periodic maintenance requirements on the unit.
Recreational Vehicle Generator
7

Generac NP-50G Recreational Vehicle Generator
AUTOMATIC CHOKE
The engine is equipped with an automatic choke that consists
of two main components — choke solenoid and prechoke.
■ CHOKE SOLENOID _
During engine cranking (start/stop switch at START), a solid
state choke module signals the choke solenoid to actuate and
cycle (choke on/choke off) until the engine starts. The choke
solenoid thus opens and closes the carburetor choke valve only
when the engine is cranking. When the engine starts, the choke
stops cycling.
■ PRECHOKE __
The choke system also has a temperature sensitive metal strip
that adjusts choke valve angle according to ambient temper¬
atures (i.e., in cold ambient temperatures, choke valve closes
more). Once the engine starts, an element heats the tem¬
perature-sensitive strip to a normal operating condition, opening
the choke valve. This may take about 3 minutes in cooler
weather.
BEFORE STARTING THE ENGINE
IMPORTANT: Instructions and information in this manual
assume the generator has been properly installed, connected,
serviced, tested and adjusted by a qualified installation tech¬
nician or installation contractor.
■ INSTALLATION _
Generator installation must have been properly completed so
it complies with all applicable codes, standards and regula¬
tions and with the manufacturer's recommendations.
■ ENGINE LUBRICATION _
Have engine crankcase properly serviced with recommended
oil before starting. Refer to MAINTENANCE and SPECIFI¬
CATIONS sections for oil servicing procedures and
recommendations.
CAUTION: Any attempt to crank or start the engine
A before you have property serviced it with the recom-
mended oil may result in an engine failure.
■ FUEL SUPPLY _
The engine must have adequate supply of proper fuel to oper¬
ate. Before starting, check that sufficient fuel is available.
NOTE: On some installation, the generator engine may “share"
the vehicles gasoline fuel tank with vehicle engine. Some instal¬
lations may provide separate fuel tanks for generator and
vehicle engine.
■ COOLING AND VENTILATING AIR
Air inlet and outlet openings in generator compartment must
be open and unobstructed for continued proper operation.
Without sufficient cooling and ventilating airflow, engine-gen¬
erator quickly overheats which causes it to shutdown or may
damage the generator.
■ ENGINE EXHAUST GAS _
Before starting the generator engine, you should be sure there
is no way for exhaust gases to enter the vehicle interior and
endanger people or animals. Close windows, doors and other
openings in the vehicle that, if open, might permit exhaust gases
to enter the vehicle.
DANGER: The generator engine gives off DEADLY
carbon monoxide gas through its exhaust system.
This dangerous gas, if breathed in sufficient con¬
centrations, can cause unconsciousness or even
death. DO NOT OPERATE THE GENERATOR IF THE
EXHAUST SYSTEM IS LEAKING OR HAS BEEN
DAMAGED. SYMPTOMS OF CARBON MONOXIDE
POISONING ARE (a) inability to think coherently;
(b) vomiting; (c) twitching muscles; (d) throbbing
temples; (e) dizziness; (f) headaches; (g) weak¬
ness and sleepiness. IF YOU FEEL ANY OF THESE
SYMPTOMS, MOVE INTO FRESH AIR IMMEDI¬
ATELY. IF SYMPTOMS PERSIST, GET MEDICAL
HELP.
STARTING THE GENERATOR
IMPORTANT: Read the vehicle manufacturer’s instructions.
The owner/operator should become familiar with the vehicle
in which this generator is installed. Differences exist between
vehicles. For example, some vehicles may use a transfer
switch to isolate dockside power from the generator, while other
vehicles may use an isolating receptacle. Some vehicles may
be equipped with a DC converter which allows the generator
to power certain DC lighting and other DC loads.
To start the generator from either the generator control panel
or from the optional Remote Panel, proceed as follows on page
9.
Recreational Vehicle Generator
8

Generac NP-50G Recreational Vehicle Generator
1. Turn OFF electrical loads, using whatever means provided
in your vehicle (such as a main line circuit breaker or trans¬
fer switch).
NOTE: If starting from the generator control panel, turn OFF
loads by setting the generators main circuit breaker to “OFP
or “OPEN". If starting from a Remote Panel, turn OFF loads
using whatever means is provided in the vehicle (such as a
main circuit breaker). Electrical load circuits will be turned ON
after the generator has started, stabilized and warmed up.
2. If you have not started the engine in more than two weeks,
press the Fuel Pump Primer switch and hold it for about 30
seconds to prime fuel system. However, if the engine is
warm, skip Step 2.
3. Hold the engine Start/Stop Switch at START to crank engine.
Release the switch when the engine starts.
CAUTION: If the engine does not start after it has
been cranking for 15 seconds, release the
start/stop switch and try again. Holding the switch
for longer than 15 seconds can damage the starter
motor.
4. Let the engine run at no-load for a few minutes to stabilize
and warm up.
5. Turn ON electrical loads, using whatever means provided
(such as a main circuit breaker or transfer switch).
STOPPING THE GENERATOR
1. T urn OFF all electrical loads, using whatever means pro¬
vided (such as a main circuit breaker or transfer switch).
2. Let generator run at no-load for a few minutes, to stabilize
internal engine generator temperatures.
3. Place Start/Stop switch in its STOP position.
If electrical loads are applied at reduced operating speeds, such
loads imposed on the engine when sufficient power is not avail¬
able may shorten engine life. Never turn ON electrical loads
until after the generator engine has started and stabilized
ON-speed.
SUMMER/WINTER
HEAT RISER SYSTEM
Under certain weather conditions, it is possible for ice to form
in the venturi area of the carburetor. This condition can be
very dangerous because it can prevent the governor system
from functioning properly, which results in a “run-away” engine.
The most common weather conditions leading to this problem
are temperatures in the range of 25° to 35°F, along with high
humidity. This ice formation can also be attributed to the load
being applied during these weather conditions. Generators
running with no load or light loads applied usually have the
most problems. The operator is responsible for adjusting the
heat riser system for weather conditions.
■ CONSTRUCTION AND FUNCTION OF
HEAT RISER SYSTEM _
The system consists of the following components:
• Plastic collector box that is attached to the back side of the
air filter base.
• “Flapper" valve and lever assembly.
• Corrugated aluminum tube that goes from the above plas¬
tic box, through engine enclosure sheet metal and nestled
very close to exhaust manifold.
Place the lever in the “Summer” position (Figure 4), to draw
air into the filter box directly from the compartment through
the tube on the right side of the plastic box.
APPLYING LOADS TO GENERATOR
When applying electrical loads to the generator, observe these
guidelines:
• Before applying electrical loads, let the generator stabilize
• and warm up for a minute or two.
• DO NOT overload the generator.
■ LET ENGINE STABILIZE
The generator supplies correct rated voltage only at proper
governed speed. Some electrical appliances may be extremely
sensitive to voltage. Incorrect voltages can damage those
appliances.
Figure 4 — Adjustment Summer/Winter Lever
Recreational Vehicle Generator

Place the lever in the “Winter” position (25 - 30°F), so the hole
in the plastic tube is covered and the aluminum tube is opened.
As mentioned previously, the end of the aluminum tube is
positioned very close to the exhaust manifold. As the engine
is running and the exhaust system heats up, heated air is drawn
through the aluminum tube, which helps to prevent ice from
forming on the carburetor.
■ DO NOT OVERLOAD THE GENERATOR
You can read the rated wattage/amperage capacity of your gen¬
erator on the generator data decal (see “Identification Record”
on Page 3).
Applying electrical loads in excess of the unit’s rated capac¬
ity will cause the engine-generator to automatically shutdown.
To avoid overloading, add up the wattage of all connected elec¬
trical lighting, appliance, tool and motor loads. This total should
not be greater than the generator’s rated wattage capacity.
• Most lighting, appliance,, tool and motor loads indicate their
required watts on their nameplate or data plate. For light
bulbs, simply note the wattage rating of the bulb.
• If a load does not show its rated wattage, multiply that load's
rated VOLTS times AMPS to obtain WATTS.
• Induction type motors (such as those that run the vehicle’s
furnace fan, refrigerator, air conditioner, etc.) need about 2-
1/2 time more watts of power for starting than for running
(for a few seconds during motor starting). Be sure to allow
for this when connecting electrical loads to the generator.
First, figure the watts needed to start electric motors in the
system. To that figure, add the running wattages of other
items that will be operated by the generator.
• Do not apply heavy electrical loads for the first two or three
hours of operation.
ADDITIONAL INFORMATION
This section discusses some the the engine protective devices,
overload protection and breaking in a new generator.
■ AUTOMATIC LOW OIL PRESSURE
SHUTDOWN _
The engine is equipped with a normally-closed (N.C.) oil pres¬
sure switch (Figure 5). Engine oil pressure holds the switch
open during cranking and operation. Should oil pressure drop
below a pre-set level, the switch contacts close and the engine
automatically shuts down.
WATTAGE REFERENCE GUIDE
RUNNING
WATTS
‘Air Conditioner (12,000 Btu).1700
Battery Charger (20 amp).500
Belt Sander (3").1000
Chain Saw.1200
Circular Saw (6-12”)...800 to 1000
Coffee Maker.1000
‘Compressor (1HP).2000
‘Deep Freeze.500
Disc Sander (9”).1200
Electric Range (one element) .1500
Electric Skillet.1250
‘Furnace Fan (1/3 HP).1200
Hair Dryer.1200
Hand Drill (1”).'.1100
Hedge Trimmer.450
Impact Wrench.500
RUNNING
WATTS
Lawn Mower.1200
Light Bulb. 100
Microwave Oven.700
‘Milk Cooler. 1100
Oil Burner on Furnace.300
Oil Fired Space Heater (140,000 Btu). 400
‘Paint Sprayer, Airless (1/3 HP).600
Radio.50 to 200
‘Refrigerator.600
Slow Cooker.200
‘Submersible Pump (1-1/2 HP).2800
‘Submersible Pump (1 HP) . 2000
‘Table Saw (10”).1750 to 2000
Television.1750 to 2000
* Allow 2-1/2 times the listed watts for starting these devices.
Recreational Vehicle Generator

Generac NP-50G Recreational Vehicle Generator
Figure 5 — Switches for Engine
Safety Shutdown
■ HIGH TEMPERATURE SHUTDOWN
A high temperature switch (Figure 5) with normaily-open (N.O.)
contacts is mounted near the oil filter. If engine temperature
were to exceed about 284°F (140°C), the switch contacts
close and the engine shuts down.
■ FIELD BOOST _
The Controller Circuit Board houses a field boost diode and
resistor which are not part of the automatic choke circuit.
These two components are part of a “field boost” circuit (Figure
6). During engine cranking only, a positive DC (battery) volt¬
age is delivered through the diode, resistor, brushes and slip
rings, and the generator rotor. Application of this voltage to
the rotor “flashes the field” whenever it is started. Flashing of
the field each time the generator starts makes sure that a suf¬
ficiently strong magnetic field is available to produce “pick-up”
voltage in the stator windings.
Figure 6 — Field Boost Circuit
■ OVERVOLTAGE PROTECTION _
A solid state voltage regulator (Figure 7) controls the gener¬
ator’s AC output voltage. This regulator supplies an excitation
current to the rotor. By regulating the rotor’s excitation cur¬
rent, the strength of its magnetic field is regulated and, in turn,
the voltage delivered to connected electrical loads is con¬
trolled. When the AC frequency is 60 Hz, voltage is regulated
at 120 volts (voltage-to-frequency ratio is 2-to-1).
Figure 7 — Solid State Voltage Regulator
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The voltage regulator also incorporates a “voltage surge pro¬
tection circuit.” This circuit prevents troublesome surges in the
generator AC output voltage. Voltage surge is a common cause
of damage to electronic equipment.
■ 25-HOUR BREAK IN PERIOD
The first 25 hours of operation is the break-in period for the
generator. Properly breaking in the generator is essential to
minimize fuel consumption and provide maximum engine per¬
formance. During this 25-hour break in period, follow this
procedure:
• Run the unit at varying electrical loads, to help seat engine
piston rings properly.
• Check engine oil level frequently. Add oil if needed. It is
normal for the generator engine to consume more oil than
is normal until the piston rings have properly seated.
• For the 75-hour operation following the break in period,
avoid light electrical loads. Load the generator at 50% (or
more) of its rated wattage capacity. Repeated light loads
during these 75 hours can cause improper seating of engine
piston rings, resulting in blowby and high oil consumption.
• After operating the unit for 25 hours, complete the tasks rec¬
ommended under “25-Hour Check Up.”
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Recreational Vehicle Generator
11

■ 25-HOUR CHECK UP _
After the 25-hour break-in period, contact an authorized ser¬
vice facility for the following maintenance. The vehicle owner
is responsible for any charges:
• Change engine crankcase oil and oil filter.
Check oil level.
• Inspect cooling and ventilation openings.
Check engine carburetor adjustments.
• Check engine ignition system.
• Inspect entire electrical system.
• Inspect the engine exhaust system.
■ ATTENTION REQUIRED AFTER
SUBMERSION _
If the recreational vehicle generator has been submerged in
water, it must NOT be started or operated. Following any sub¬
mersion in water, have an authorized Generac Service Facility
thoroughly clean and dry the generator.
■ OPERATION IN HIGH GRASS
OR BRUSH _
Never operate the generator while the vehicle is parked in high
grass, weeds, brush or leaves. Such materials can ignite and
burn from the heat of the exhaust system. The generator
exhaust system becomes extremely hot during operation and
remains hot for a long time after it has shut down.
■ OPERATING PRECAUTIONS _
Never operate the generator set while the vehicle is parked
over dry leaves, dry grass or any other combustible sub¬
stance. The generator’s exhaust system becomes extremely
hot and can cause fire if it is too close to combustible mate¬
rials.
The generator’s exhaust system gives off DEADLY carbon
monoxide gas. This dangerous gas, if breathed in sufficient
concentrations, can cause unconsciousness and even death.
Never operate the generator set with the vehicle inside any
garage or other enclosed area. Never operate the generator
if it has a leaky exhaust system. Close windows in the vicin¬
ity of the generator exhaust outlet and take any other steps
to prevent exhaust gases from entering rooms or areas occu¬
pied by people or animals.
■ EFFECTS OF MOISTURE AND DIRT
Keep the generator set as clean and dry as possible. Protect
the unit against excessive dust, dirt, corrosive vapors, road
splash, etc. Permitting dirt and moisture to accumulate on gen¬
erator windings will have an adverse effect on the insulation
resistance of those windings.
When moisture is allowed to remain in contact with windings,
some of the moisture will be retained in voids and cracks in
the insulation. This causes a reduced insulation resistance
and will eventually cause problems. Dirt will make the prob¬
lem worse, since dirt tends to hold moisture in contact with
windings. Salt (as from sea air) will also worsen the problem
since it tends to absorb moisture from the air. Salt and mois¬
ture, when combined, for a good electrical conductor.
Recreational Vehicle Generator

Generac NP-50G Recreational Vehicle Generator
FUEL REQUIREMENTS
The “NP” series generator is equipped with a gasoline fuel
system. Specific installations may provide either a separate
fuel tank for the generator, or the generator may “share” the
vehicle engine’s fuel tank.
NOTE: Some installations using a “shared” fuel tank may have
a generator fuel pickup tube that is shorter than the vehicle
engine’s pickup tube. Such an arrangement causes the gen¬
erator engine to “run out of gas” while adequate fuel for the
vehicle remains in the tank.
To reduce lead and carbon deposits use high quality
UNLEADED gasoline with the generator. Leaded REGULAR
grade gasoline is an acceptable substitute.
NOTE: Using “Unleaded" gasoline contributes to longer
engine valve life by reducing lead and carbon deposits.
CAUTION: Generac does not recommend using
any gasoline containing alcohol (such as “gaso-
hoi”). If you use any gasoline containing alcohol,
It must not contain more than 10 percent ethanol
and it must be removed from the generator during
storage. Do NOT use any gasoline containing
methanol. If you use gasoline with alcohol,
inspect more frequently for fuel leaks and other
abnormalities.
ENGINE OIL REQUIREMENTS
Use only high quality detergent oil rated with API service clas¬
sification SF, SG, or SH. The recommended oil weights include
the following:
• During summer months: SAE 30. An acceptable substitute
isSAE 10W-30.
• During winter months: SAE5W30. DO NOT USE SAE 10*
W40.
Crankcase and oil filter capacity is about 1400ml or about 1.5
U.S. quarts. Use no special additives. See “Maintenance" sec¬
tion for oil level check and fill procedures.
SPECIFICATIONS
■ ENGINE
Type of Engine.
Cooling Method.
Rated Horsepower.
Displacement.
Cylinder Block.
Type of Governor.
Air Cleaner.
Starter.;.
Ignition System.
Recommended Spark Plugs
Champion.
AC.
Ram Autollte.
Spark Plug Gap.
Recommended Minimum Battery
.GN-410, single-cylinder
.Air-cooled
.15 at 4200 RPM
.407cc
.Aluminum with cast iron sleeve
.Mechanical, fixed speed
Paper element with foam pre-cleaner
.12 volt DC electric
.Solid State with flywheel magneto
.RC12YC
.R45S
.65
.0.030 inch (0.76mm)
.400 CCA (cold cranking amps)
■ GENERATOR
Rotor RPM.3600
Rotor Poles.2
Engine RPM.2571
Rated Maximum Continuous
AC Output.4800 watts (4.8 kW)
Voltage . r.. 1 2 0 volts AC*
Rated Maximum Continuous AC Current.40 amperes**
Phase.single
Frequency.60 Hertz
Battery Charge Voltage.14 Volts DC
Battery Charge Current.2 amperes (max)
Weight.197 pounds (93 kg)
Length.25 inches (635mm)
Width.18.5 inches (470mm)
Height.15.75 inches(400mm)
* All units are reconnectable to 120 and/or 240 volts, dual voltage output.
Units are no longer listed per RVIA/ANSI when reconnected for dual volt¬
age output.
“ If reconnected for dual voltage, the ampere rating for 240 volts is 20 AC
amperes.
Recreational Vehicle Generator
13

This section includes information about simple maintenance
which includes the following tasks.
• Checking engine oil level.
• Changing engine oil.
• Changing oil filter.
• Changing the air cleaner.
• Cleaning the air intake screen.
• Cleaning spark plug.
CHECKING ENGINE OIL LEVEL
Check engine crankcase oil level at least every eight hours of
operation, or before you use it.
Be sure the generator is as level as possible.
• Remove OIL DIPSTICK (Figure 8) and wipe it dry with
clean, lint-free cloth.
• Install and tighten oil dipstick then remove again.
• Oil level should be at the dipstick “FULL" mark. If necessary,
add oil to the “FULL" mark only. DO NOT FILL ABOVE THE
“FULL” MARK.
• Install and tighten oil dipstick before operating the engine.
NOTE: See “Engine Oil Requirements" on Page 13 for rec¬
ommended oils.
Figure 8 —Oil Dipstick and Fill Tube
CHANGE ENGINE OIL
Change engine oil after the first 25 hours of operation (after
the 25-hour break-in period, Page 11). Thereafter, change oil
every 50 operating hours. Change oil more frequently if oper¬
ating consistently under heavy load or at high ambient
temperatures. To change oil, proceed as follows:
• Run engine for at least 5 minutes, then shut down.
Recreational Ve
• With engine still warm, remove oil drain cap from oil drain
hose (Rgure 9). Drain oil completely into a suitable container.
Figure 9 — Location of Oil Drain Cap
• Remove oil dipstick and fill crankcase with the recom¬
mended oil (see Page 13). The engine crankcase can hold
about 1.4 liters. DO NOT FILL ABOVE “FULL” MARK.
• Install and tighten dipstick before operating engine.
CHANGE OIL FILTER
Change engine oil filter after the first 25 hours of operation,
every 100 operating hours thereafter.
• Turn oil filter counterclockwise to remove (Figure 10).
• Coat gasket of new filter with engine oil.
• Turn new filter clockwise until its gasket contacts lightly with
the filter adapter. Then tighten with an additional 3/4 to one
turn by hand.
• Run engine and check for leaks.
NOTE: Check oil level and fill to full mark after checking for
leaks. Filter will retain some oil.
TO REMOVE
icle Generator
14

ENGINE AIR CLEANER
Clean and re-oil the foam pre-cleaner every three months or
every 25 operating hours, whichever comes first. Service more
frequently if operating under extremely dusty or dirty condi¬
tions (Figure 11):
• Remove both screws.
• Remove the COVER, FOAM PRE-CLEANER and PAPER
FILTER.
• Remove foam pre-cleaner from cover.
• Wash foam pre-cleaner in liquid detergent and water.
• Wrap foam pre-cleaner in a cloth and squeeze dry.
• Saturate foam pre-cleaner in engine oil. Squeeze to remove
excess oil (Do not twist foam prercleaner).
• Install foam pre-cleaner into cover, followed by paper filter.
• Install cover, foam pre-cleaner and paper filter.
• Tighten both screws.
Once each year or every 100 hours of operation (whichever
comes first), replace the paper filter. The new replacement
filter must be a flame retardant type.
■ CLEAN OR REPUCE PAPER
AIR FILTER
Remove air cleaner cover; then remove foam pre-cleaner
(service if necessary) and remove paper filter.
Clean air filter by tapping it gently on a solid surface. If the
filter is too dirty, replace it with a new one. Dispose of the
old filter properly.
Clean air cleaner cover then insert pre-cleaner into cover.
Next insert new paper filter into cover to hold pre-cleaner
in place and assemble all of them to the base of the air
cleaner.
CLEAN AIR INTAKE SCREEN
Clean all foreign material from air intake screen (Figure 12)
at least once every 100 hours of operation. Clean more often
if necessary.
Inspect the area around the generator exhaust muffler peri¬
odically and remove all grass leaves, dirt, etc.from this area.
Figure 12 — Cleaning Air Intake Screen
ENGINE SPARK PLUG
Clean engine spark plug and set gap to 0.030 inch (0.76mm)
every 100 hours of operation (Figure 13). Clean by scraping
or wire brushing and washing with commercial solvent. DO
NOT BLAST CLEAN SPARK PLUG.
CAUTION: Sparking can occur If wire terminal
does not fit firmly on spark plug terminal end. If
necessary, reform wire terminal to obtain a tight fit.
Figure 13 — Setting Spark Plug Gap
Recreational Vehicle Generator
15

FUEL FILTER
Remove and replace fuel filter (Figure 14) every 100 hours of
operation or once each year, whichever comes first.
SPARK ARRESTOR MUFFLER
If the generator is not equipped with a spark arrestor exhaust
muffler and is to be used on any forest covered, brush cov¬
ered or grass covered unimproved land, you may have to
install a spark arrestor. The spark arrestor must be maintained
in effective working order by the vehicle owner/operator.
For assistance in ordering, installing and maintaining spark
arrestor exhaust mufflers, contact your nearest authorized
service facility.
Exhaust mufflers supplied by Generac are spark arrestor
types. Generac exhaust muffler for recreational vehicle gen¬
erators do not have a spark arrestor screen, but are of the more
efficient “toroid” or “swirl" type. To remove carbon and com¬
bustion deposits from such mufflers, remove the PLUG from
the muffler and run engine for about 15 minutes. Shut engine
down, let the muffler cool and install the plug.
CLEANING THE GENERATOR
Keep your generator set as clean and dry as possible. Dirt
and moisture that are permitted to accumulate on electrical
windings have an adverse affect on the insulation resistance
of those windings.
Moisture that is allowed to remain in contact with windings will
be retained in voids and cracks of the windings. Dirt makes
the problem worse, since it tends to hold the moisture into con¬
tact with the windings. Salt, as from sea air, worsens the
problem since it tends to absorb moisture from the air. The
combination of salt and moisture makes a good electrical con¬
ductor.
~7~\ CAUTION! Do NOT use a forceful spray of water to
A clean the generator. Water will enter the generator
_interior and cause problems, and may also contam¬
inate the generator fuel system.
BATTERY
All lead-acid storage batteries will discharge when not in use.
The generator battery should be inspected as follows:
■ ONCE WEEKLY _
Inspect battery posts and cables for tightness, corrosion.
Clean and/or tighten as needed.
Also check battery fluid level, and, if necessary, fill with DIS¬
TILLED WATER ONLY. DO NOT USE TAP WATER IN
BATTERY.
■ EVERY SIX MONTHS _
Have battery state of charge and condition checked. This
should be done with automotive type battery hydrometer.
WARNING: Be sure to re-install the plug from the
^ muffler tightly. Engine vibration could cause a
-loose plug to fall out. Without the plug in place,
hot engine exhaust is directed out the opening.
This hot exhaust, depending on the installation,
could be directed to areas not able to withstand
the extreme heat such as wooden floor boards or
other flammable material. This could result in a
fire.
DANGER: Storage batteries give off explosive
hydrogen gas. This gas can form an explosive
mixture around the battery for several hours after
charging. The slightest spark can ignite the gas
and cause an explosion. Such an explosion can
shatter the battery and cause blindness or other
injury. Any area that houses a storage battery
must be properly ventilated. Do not allow smok¬
ing, open flame, sparks or any spark producing
tools or equipment near the battery.
Recreational Vehicle Generator

DANGER: Battery electrolyte fluid is an extremely
caustic sulfuric acid solution that can cause
severe bums. Do not permit fluid to contact eyes,
skin, clothing, painted surfaces, etc. Wear protec¬
tive goggles, protective clothing and gloves when
handling a battery. If you spill the fluid, flush the
affected are immediately with dear water.
DANGER: Do not use any jumper cables or
booster battery to crank and start the generator
engine. If any battery has discharged, remove It
for recharging.
MAJOR SERVICE MANUAL
To obtain a service manual for your generator, order it from
your dealer/distributor or contact the factory. Be sure to iden¬
tify your MODEL NUMBER and SERIES.
DRIVE BELTS
The engine drives the generator rotor by means of a pulley
and drive belt arrangement. The drive belt and pulleys are war¬
ranted for the life of the generator. Drive belt tension was
properly adjusted before the unit was shipped from the fac¬
tory. If you suspect that drive belt tension is incorrect, contact
an authorized service facility.
EXERCISING THE GENERATOR
Generac recommends that you start and operate the gener¬
ator at least once every seven days. Let the unit run for at
least 30 minutes to “exercise" the engine.
OUT OF SERVICE PROTECTION
If you cannot exercise the generator every seven days and it
is to be out of service longer than 30 days, prepare the gen¬
erator for storage as follows:
• Start the engine and let it warm up.
• Close the fuel shutoff valve in the fuel supply line and let
the engine “run out of fuel.”
• While the engine is still warm from running, drain the oil com¬
pletely. Refill crankcase with SAE 10W30 oil having API
classification “For Service SF.”
• Attach a tag to the engine indicating the viscosity and clas¬
sification of the oil in the crankcase.
• Remove spark plug and pour about two or three table¬
spoons of clean, fresh engine oil into spark plug threaded
opening. Crank engine several times to distribute oil, then
install and tighten spark plug.
• Remove the battery and store in a cool, dry room on a
wooden board. Never store the battery on concrete or earth
floors.
• Clean and wipe the entire generator.
RETURN THE UNIT TO SERVICE
AFTER STORAGE
To return the unit to service after storage, proceed as follows:
• Check tag on engine for oil viscosity and classification.
Verify that the correct recommended oil is used in engine.
If necessary, drain and refill with proper oil.
• Check battery. Fill all cells to the proper level with distilled
water. DO NOT USE TAP WATER IN THE BATTERY.
Recharge battery to 100% state of charge, or, if defective,
replace the battery.
• Turn OFF all electrical loads, add fuel if necessary, then start
the engine.
• Let the engine warm up.
• Apply electrical loads to at least 50% of the unit’s rated
wattage capacity.
• When engine is thoroughly warmed up, shut it down.
THE GENERATOR IS NOW READY FOR SERVICE.
Recreational Vehicle Generator

TROUBLESHOOTING POINTS
PROBLEM CAUSE CORRECTION
Engine won't crank.
1. 15 amp fuse blown. 1.
Replace fuse.
2. Loose or corroded or defective
battery cables
2.
Tighten, clean or replace
as necessary.
3. Battery is discharged or defective. 3. Recharge or replace battery.
4. Defective starter contactor. 4.
Replace if defective.
5. Defective starter motor.
5
Replace if defective.
Engine cranks but won't start 1. Out of fuel.
1 . Replenish fuel.
2. Fuel shutoff valve is closed. 2.
Open fuel shutoff valve(s).
3. Fuel pump not operating
3. Repair or replace if defective.
4. Automatic choke not operating properly.
4.
Repair, replace or adjust.
5. Engine is flooded.
5.
Wait 5-10 minutes; try again.
6. Fuel Filter is clogged. 6. Replace filter if clogged.
7. Defective Controller Circuit Board.
7.
Replace bad circuit board
8. Engine spark plug defective. 8. Clean, regap or replace as needed.
9. Bad ignition magneto on engine. 9. Replace if defective.
10. Bad carburetor. 10.
Adjust, repair or replace.
11. Dirty air cleaner. 11.
Clean or replace as needed.
Engine starts hard, runs rough. 1. Dirty engine air cleaner.
1 .
Clean or replace as needed.
2. Automatic choke is sticking.
2.
Free choke linkage as needed.
3. Defective spark plug.
2. Clean, regap or replace plug.
4. Defective ignition magneto.
4.
Replace if defective.
Engine starts, then shuts down
1. Engine oil level is low. 1.
Check oil and add oil as needed.
2. Defective Low Oil Pressure Switch
2. Replace bad switch.
No AC output voltage.
1. Main breakers open. 1 .
Close main breakers.
2. Transfer switch (if so equipped)
is set to wrong position.
2.
Reset transfer switch.
3, Failure in vehicle electrical system.
3. See vehicle manual.
4. Generator component failure.
4.
Contact an authorized service
facility.
Recreational Vehicle Generator

Generac NP-50G Recreational Vehicle Generator
Drawing No. 94210
ELECTRICAL DATA

Drawing No. 92197
EXPLODED VIEW - BASE AND PULLEYS