Master MGH3000 Quick start guide

PORTABLE GASOLINE
GENERATORS
OWNER’S OPERATION AND INSTALLATION MANUAL
R
Generator Models: MGH3000, MGH4000A, MGH5000A, MGH6000, and MGH7000
IMPORTANT
Read and understand this manual before operating or servicing
generator. Improper use of generator can cause serious injury.
Keep this manual for future reference.
FUEL
F
RESET
120/240 VOLTS
120
240V
FULL POWER
SELECTOR
120
ONLY
RESET
TEST
RESET
120 VOLTS
RESET

2
SECTION PAGE
Safety Information....................................................................... 3
Product Identification .................................................................. 6
General Information .................................................................... 7
Specifications ..............................................................................7
Unpacking ................................................................................... 7
Ventilation ................................................................................... 8
Dust, Dirt, Rain, and Snow .........................................................8
High and Low Temperature Operation ....................................... 8
Generator Features ...................................................................... 9
Oil Alert System ...................................................................9
Full Power Selector Switch .................................................. 9
Electric Start (Model MGH7000 Only)................................9
Ground Fault Circuit Interrupter Receptacle......................10
Engine Circuit Breaker (Model MGH7000 Only)..............10
Receptacle Circuit Breaker ................................................. 11
Engine Oil.................................................................................. 11
Fuel ............................................................................................12
Battery (Model MGH7000 Only).............................................. 12
Generator Grounding................................................................. 15
Extension Cords ........................................................................ 16
Standby Installation To Home Or Building ..............................16
Determining Electrical Load For Generator .............................16
Operation ...................................................................................18
General Information............................................................ 18
Using Receptacle ................................................................18
Power Cord and Plug Requirements...................................19
Prestart ................................................................................20
Starting................................................................................ 20
High Altitude Operation ..................................................... 22
Adding Electrical Loads ..................................................... 22
Disconnecting Electrical Loads .......................................... 22
Stopping Engine..................................................................23
Maintenance and Repairs .......................................................... 24
Storage....................................................................................... 24
Troubleshooting.........................................................................25
Electrical Component Specifications ........................................25
Wiring Diagrams ....................................................................... 26
Parts Centrals.............................................................................27
Technical Service ......................................................................28
Servicing The Engine ................................................................28
Replacement Parts ..................................................................... 28
Accessories ................................................................................ 28
Illustrated Parts Lists ........................................................... 29-34
Warranty Information.................................................Back Cover
CONTENTS

3
SAFETY
INFORMATION WARNINGS
IMPORTANT: Read this owner’s manual and the engine owner’s
manual carefully. Become familiar with this generator before trying to
operate or service it. Know its uses, limitations, and any hazards
involved. Improper use of generator can cause severe injury or death
from explosion, fire, burns, electrical shock, or carbon monoxide
poisoning.
DANGER
Carbon monoxide poisoning may lead to death!
Engine exhaust contains poisonous carbon monoxide gas. Overexposure will
cause loss of consciousness and will lead to death. Use only in well-vented areas.
Make sure area has plenty of free-moving, fresh, outside air. Never run generator
in an enclosed or confined area. Never run generator inside occupied building.
Early signs of carbon monoxide poisoning resemble the flu, with headaches,
dizziness, and nausea. If you have these signs, get fresh air at once! Some people
are more affected by carbon monoxide than others. These include pregnant
women, persons with heart or lung disease or anemia, those under the influence of
alcohol, and those at high altitudes. Make certain you read and understand all
warnings. Keep this manual for reference. It is your guide to safe and proper
operation of this generator.
Safety information appears throughout these instructions. Pay close attention to
them. Below are definitions for the safety information listed throughout this
manual.
DANGER indicates a hazard which will cause severe personal injury,
death, or substantial property damage if you ignore warning.
WARNING indicates a hazard which can cause severe personal injury,
death, or substantial property damage if you ignore warning.
CAUTION indicates a hazard which will or can cause minor personal
injury or property damage if you ignore warning.
1. !WARNING Gasoline presents a hazard of fire or explosion. Gasoline is
flammable. Its vapor is explosive.
• Keep fuel out of children’s reach.
• Refuel generator in a well-vented area. Do not fill fuel tank in the dark. Do
not refuel while engine is running. Unhook all electrical loads and shut off
engine before refueling.
• Do not overfill fuel tank. Always allow room for fuel to expand. If you
overfill tank, fuel can overflow onto hot generator. This can cause fire or
explosion. After refueling, tightly close fuel tank cap.
• Do not spill fuel. Fuel or fuel vapor may ignite. If fuel spills, make sure
area is dry before starting engine.
• Never smoke in refueling area. Never allow open flames or sparks in area.
• Store fuel in approved container. Store fuel in a well-vented area free of
open flames or sparks.
Continued

4
SAFETY
INFORMATION
Continued
2. !WARNING Guard against fire hazard. Keep operation area well-vented.
Keep generator at least three feet away from any object. Do not place flam-
mable objects near generator.
• Do not use generator where flammable vapors are present. Some vapors
are heavier than air. These vapors settle in low-lying places.
• Do not use generator in enclosed spaces. This includes motor home or RV
generator compartments.
3. !WARNING Guard against electric shock. Generator produces high voltage.
This high voltage can cause severe electric shock. Only responsible adults
should use generator.
• Properly ground generator before starting.
• Never let anyone operate or service generator without proper instructions.
• Avoid contact with live terminals or bare wires.
• Do not use generator outdoors in rain or snow.
• Do not use generator near standing water or snow.
• Do not use if generator is wet or damp.
• Do not use generator in highly conductive areas. These areas include metal
decking and steelwork.
• Only use grounded extension cords.
• Do not use any worn or damaged electric cords. Electric shock or damage
to generator may result.
• Do not wear damp clothing or wet shoes when using generator.
4. !WARNING Guard against burns. Hot engine parts can cause severe injury.
Use caution and remain alert when using generator.
• Keep children and animals away from generator while it is running or hot.
• Keep all covers and shields in place. Keep them tightly secured.
• The muffler becomes very hot during operation. The muffler remains hot
for a while after shutdown. Do not touch muffler while it is hot. Do not let
muffler touch anything flammable. Let engine cool before transporting or
storing.
5. !WARNING Have standby installation to home or building performed by a
licensed electrician. Do not let anyone else wire into a utility circuit. Personal
injury, equipment damage, or damage to home could occur.
6. !WARNING Never connect generator to any existing electrical circuits. The
generator output will back-feed into the utility power line. This may electro-
cute a power company line repair person. Also, if generator is powering
electrical circuits, the chance of an electrical fire exists.
7. !WARNING Battery gives off explosive gases. Keep sparks, flames, and
cigarettes away. Do not remove or install battery cables when engine is
cranking or running. Only service or use battery in a well-vented area.
Continued

5
SAFETY
INFORMATION
Continued
8. !WARNING Battery contains sulfuric acid. Battery acid is poisonous if
swallowed. Contact with skin or eyes may cause severe burns. Do not tilt
generator with battery installed. Tilting could cause battery acid to spill. Wear
protective clothing and face shield when servicing. Keep out of children’s
reach.
9. !WARNING Only a qualified electrical service person should service and
repair generator.
• Generator produces high voltage. Use extreme caution when working on
electrical parts.
• Always remove spark plug wire from spark plug before servicing. This
will prevent accidental starting.
• When working on generator, avoid hot muffler, exhaust manifold, and
engine parts. Severe burns may occur.
• Do not work on generator when tired.
• Use only factory approved replacement parts.
10. !WARNING Store generator in a well-vented area. Make sure fuel tank is
empty. Never store with fuel in tank. Vapors may reach an open flame or
spark. Fire or explosion may result.
11.
!
CAUTION
Never operate generator
• if engine speed changes greatly
• if engine misfires often
• if powered items overheat
• if electrical output drops
• if it is sparking
• if it produces smoke or flames
• if it vibrates at high levels
• if it has a damaged receptacle
12.
!
CAUTION
Keep generator and nearby areas clean.
• Keep generator free of oil, mud, and other foreign matter.
• Remove anything that creates slippery areas around generator.
• Remove oily rags and other items that create fire hazards.
• Keep a fire extinguisher nearby. Make sure it is rated ABC by the NFPA.
They are good for all uses. Consult your local fire department.
• Keep fire extinguisher well maintained. Be familiar with its use.
13.
!
CAUTION
Know how to stop engine quickly. Know how to use all
controls.
14.
!
CAUTION
Prolonged exposure to loud noise can cause hearing loss.
• When working around generator, wear approved hearing protection.
• Remember neighbors when using generator.

6
FUEL
F
FUEL
F
FULL POWER
SELECTOR
120
ONLY 120
240V
RESET
TEST
RESET
120 VOLTS
120/240 VOLTS
RESET
RESET
Control
Panel
Gas Cap/Fuel Gage
PRODUCT
IDENTIFICATION
Circuit
Breaker
120/240 Volt
Receptacle
Roll Cage
120 Volt
Receptacle
(GFCI)
Full Power
Selector
Switch
120 Volt
Receptacle
Run
Lamp
Provision for
Auto-Idle Switch
Gas Tank
Starter Grip
Choke
Lever
Fuel
Valve
Lever
Oil Dipstick
Ground
Lug
Alternator
Engine Engine
ON/OFF
Switch
Figure 1 - Portable Generator (Model MGH4000A Shown)

7
GENERAL
INFORMATION
Master portable generators are rugged and compact. These models provide depend-
able, trouble-free service. The alternators are brushless with revolving fields. Honda
gasoline engines provide long life under heavy use. Honda engines have overhead
valves (OHV). This provides high performance with lower fuel consumption. These
engines are governed to maintain engine speed of 3600 RPM under load. 3600 RPM
engine speed provides 120/240V, 60 Hz power.
Additional Features
• Circuit breaker protection
• Spark-arresting muffler
• Large fuel tank
• Oil alert system
• Electric starter (model MGH7000 only)
• 15-Amp ground fault circuit interrupter (GFCI) receptacle
SPECIFICATIONS MODEL
MGH3000 MGH4000A MGH5000A MGH6000 MGH7000
Electrical Specifications
Rated Wattage 2500 4000 5000 6000 6800
Rated Amperage
120 Volt 20.8 33.3 41.7 50 57
240 Volt –– 16.7 20.8 25 28.3
Receptacle Specifications
120-Volt, 15-Amp GFCI Yes Yes Yes Yes Yes
120-Volt, Twist-Lock No 30 Amp 30 Amp 30 Amp 30 Amp
120/240-Volt, Twist-Lock No 20 Amp 20 Amp 20 Amp 30 Amp
120-Volt Full-Power Switch No Yes Yes Yes No
General Specifications
Honda Engine H.P. 5.5 8 9 11 13
Honda Model GX160K1VX GX240K1VA GX270VA GX340K1VA GX390K1VXE
Fuel Type Gasoline Gasoline Gasoline Gasoline Gasoline
Fuel Tank Capacity 3.9 qt. 5 gal. 5 gal. 5 gal. 5 gal.
Oil Alert System Yes Yes Yes Yes Yes
Start Method Recoil Recoil Recoil Recoil Electric
Weight (pounds) 85.5 139 173 191 247
* Single-phase, 1.0 power factor
Note: Ratings apply to SAE standard conditions. Reduce ratings 3 1/2% for each 1000 feet
above sea level and 1% for each 10°Fahrenheit rise above 60°F.
UNPACKING 1. Remove generator from carton.
2. Remove any protective packaging applied to generator for shipment.
3. Check for loose or missing parts. Check for shipping damage. If any parts are
missing or damaged, promptly inform dealer where you bought generator.
4. Battery cables are supplied for model MGH7000 only. These cables are in a
separate bag inside generator carton. You must install these cables to engine.
See Battery, page 12 for installation instructions.

8
VENTILATION DANGER
Use only in well-vented areas. Make sure area has
plenty of free-moving, fresh, outside air. Never run
generator in an enclosed or confined area. Never run
generator inside occupied building. Engine exhaust
contains poisonous carbon monoxide gas.
Overexposure will cause loss of consciousness
and will lead to death.
This generator needs cooling air to run properly. Never block free-flowing,
cooling air to generator. Overheating will occur without cooling air. This will
damage the generator. Keep generator at least three feet away from any object.
WARNING
Do not use generator outdoors in rain or snow. Do
not use generator near standing water or snow. Do
not use if generator is wet or damp. Operating
generator in these conditions increases the risk of
electrocution. Severe injury or death can occur.
Do not use generator in extremely dusty or dirty conditions. This will severely
affect its life. Keep generator clean. Do not allow dust, dirt, rain, or snow to
collect on it. Protect generator from outdoor elements.
DUST, DIRT,
RAIN, AND
SNOW
HIGH AND LOW
TEMPERATURE
OPERATION
Air temperature affects generator output. Output drops 1% for each 10°tempera-
ture rise above 60°F. Very low temperatures may make the engine hard to start.
See engine owner’s manual for more information.

9
IMPORTANT: Do not move the full power selector switch while powering
electrical items. Unplug all items before moving switch. Failure to do so can
damage switch. Model MGH7000 does not have this switch. This model provides
full power to all receptacles.
120/240 VOLT Position
120 VOLT ONLY Position
Figure 3 - Full Power Selector Switch
GENERATOR
FEATURES
OIL ALERT SYSTEM
The oil alert system protects the engine from low oil damage. This system auto-
matically shuts down the engine and prevents engine restarting if the oil level falls
too low.
Note: When this happens, the engine switch remains in the ON position. The oil
alert system is wired into the ON/OFF Switch.
If this system shuts down the engine, the engine will not start until you add oil.
Add oil to engine (see Engine Oil, page 11).
Note: Operate generator on a level surface. If not level, the oil may flow away
from the oil level sensing device. This will cause the oil alert system to shut down
engine.
See engine owner’s manual for more information.
Figure 2 - Engine Switch Location
120V
ONLY 120 240V
FULL POWER
SELECTOR
120V
ONLY 120 240V
FULL POWER
SELECTOR
HONDA
OFF ON START
ENGINE SW
CIRCUIT
BREAKER
FULL POWER SELECTOR SWITCH
All models except MGH3000 and MGH7000 have a full power selector switch on
the control panel. The switch has two positions: 120 VOLT ONLY, and 120/240
VOLT.
120 VOLT ONLY: This position sends full power to the 120V receptacles only.
240V power is not available. Use this position when powering 120V items only.
120/240 VOLT: This position sends full power to the 120/240V receptacle. It also
powers the 120V receptacles at reduced wattage capacity.
ELECTRIC START (Model MGH7000 Only)
Model MGH7000 has an electric starter. A battery is not supplied with generator.
You must provide a 12-volt, 32-amp-hour battery. For more battery information,
see Battery, page 12.
ENGINE SW
ON
OFF
All Models
Except
MGH7000 Model
MGH7000
Only

10
GROUND FAULT CIRCUIT INTERRUPTER RECEPTACLE
All models have a 120-volt ground fault circuit interrupter (GFCI) receptacle. The
GFCI receptacle is on the control panel or top cover of alternator (model
MGH3000 only). The GFCI protects you against hazardous electrical shock
caused when your body becomes a path through which electricity travels to reach
ground. This could happen when you touch an appliance or cord that is ‘live’
through faulty mechanism, damp or worn insulation, etc.
When protected by the GFCI, you may still feel a shock, but the GFCI should cut
it off quickly. A person in normal health should not receive serious injury.
Note:
Infants and very small children may still be affected.
Test Procedure
Check the GFCI receptacle every month. This insures it is working right.
1. Push black TEST button. Red RESET button should pop out. This should trip
GFCI, resulting in no electrical power at receptacle. Verify this by plugging
test lamp with good bulb into receptacle. If lamp does not work, GFCI recep-
tacle is good.
WARNING
If RESET button does not pop out, do not use the GFCI
receptacle. Contact a qualified electrician for repairs.
2. If the GFCI receptacle tests okay, restore power by pushing the RESET button
back in. The test lamp should work at this time.
IMPORTANT: You must
press the RESET button firmly and fully. It should lock into place. If the GFCI
does not lock into place, do not use receptacle. Contact a qualified electrician
for repairs.
GENERATOR
FEATURES
Continued
OFF ON START
ENGINE SW
CIRCUIT
BREAKER
ON/push OFF
Figure 5 - Engine Circuit Breaker
Engine Circuit
Breaker Button
ENGINE CIRCUIT BREAKER (Model MGH7000 Only)
This circuit breaker protects the battery charging circuit. A short circuit will trip
the circuit breaker. The circuit breaker will also trip if you install battery wrong.
Push circuit breaker button to reset.
RESET
TEST
Figure 4 - GFCI Receptacle

11
RECEPTACLE CIRCUIT BREAKER
The circuit breakers protect the receptacles and alternator. Overloading generator
will trip circuit breaker. A short circuit in item being powered will also trip
breaker. If this occurs, unplug electrical load from receptacle. Let circuit breaker
cool down. Push circuit breaker button to reset.
Electric motors need higher starting current. They require up to three-times their
rated wattage to start. The starting current needed may be too high. This can cause
nuisance circuit breaker tripping. To help prevent this, start electric motors first.
Connect additional items to generator after starting motors. If this continues to
happen, reduce the total generator load.
20
20
TrippedNormal
Figure 6 - Receptacle Circuit Breaker Button
ENGINE OIL We ship the generator without oil in the engine crankcase. You must add oil
before starting engine. See engine owner’s manual for specific oil type.
CHECKING OIL LEVEL AND ADDING OIL
Follow steps below to check oil level. Make sure engine is level and stopped.
1. Remove dipstick (see Figure 7). Wipe dipstick clean.
2. Insert dipstick into oil filler neck. Do not screw it in. Oil level should be at top
of filler neck. Oil should cover most of dipstick.
3. If level is low, fill to top of oil filler neck (see Figure 7). Only use oil recom-
mended in engine owner’s manual.
Note: If oil level is too low, oil alert system will shutdown engine and prevent
engine from restarting.
Figure 7 - Checking Oil Level
GENERATOR
FEATURES
Continued
Oil Level
At Top Of
Filler Neck
Dipstick
Oil

12
FUEL
Continued
WARNING
Battery gives off explosive gases. Keep sparks,
flames, and cigarettes away. Do not remove or install
battery cables when engine is cranking or running.
Only service or use battery in a well-vented area.
WARNING
Battery contains sulfuric acid. Contact with skin or
eyes may cause severe burns. Do not tilt generator
with battery installed. Tilting could cause battery
acid to spill. Wear protective clothing and face shield
when servicing. Keep out of children’s reach.
• If battery acid gets on your skin, wash with water.
• If battery acid gets in your eyes, flush with water
at least 15 minutes. Call a doctor at once. Battery
acid is poisonous.
• If swallowed, drink large amounts of water or
milk. Follow with milk of magnesia or vegetable
oil. Call a doctor at once.
WARNING
Gasoline presents a hazard of fire or explosion.
Gasoline is flammable. Its vapor is explosive.
• Keep fuel out of children’s reach.
• Refuel generator in a well-vented area. Do not fill
fuel tank in the dark. Do not refuel while engine is
running. Unhook all electrical loads and shut off
engine before refueling.
• Do not overfill fuel tank. Always allow room for
fuel to expand. If you overfill tank, fuel can over-
flow onto hot engine. This can cause fire or
explosion. After refueling, tightly close fuel tank
cap.
• Do not spill fuel. Fuel or fuel vapor may ignite. If
fuel spills, make sure area is dry before starting
engine.
• Never smoke in refueling area. Never allow open
flames or sparks in area.
• Store fuel in approved container. Store fuel in a
well-vented area free of open flames or sparks.
Use clean, fresh, unleaded gasoline. Use gasoline with octane rating of 86 or
higher. Service station gasoline pumps should display the octane rating. Using
gasoline with lower octane level could damage engine. Avoid getting dirt, dust, or
water in fuel tank. Do not mix oil with gasoline.
See engine owner’s manual for more information.
BATTERY
(Model MGH7000 Only)

13
CAUTION
If you remove battery, insulate the red, positive (+)
battery cable terminal. Insulate with electrical tape.
Exposed terminal may spark when generator runs.
IMPORTANT: Make sure battery connections are the correct polarity. Electric
start generators use negative ground, 12-volt DC starting system.
Model MGH7000 has an electric starter. A battery is not supplied with generator.
You must provide a 12-volt, 32-amp-hour battery. The positive and negative
battery cables are supplied with generator. You must install these cables before
mounting battery.
Always wear safety glasses when working with battery. Make sure battery termi-
nals are clean. Make sure cable connections are tight.
Always shut down engine before removing or attaching battery cables. Always
remove the negative (–) cable first. Always attach negative (–) cable last.
INSTALLING BATTERY CABLES TO ENGINE
1. Attach the red, positive (+) battery cable to the starter solenoid on engine (see
Figure 8).
2. Attach the black, negative (–) battery cable to the engine block. Use the bolt,
nut, and two washers provided with the battery cables. Use long mounting hole
on opposite side of engine from starter solenoid. Attach cable as shown in
Figure 9.
Starter
Solenoid
Figure8-ConnectingRed,Positive(+)BatteryCabletoEngineStarterSolenoid
Continued
Figure 9 - Connecting Black, Negative (–) Battery Cable to Engine Block
Red, Positive
(+) Battery
Cable
Black, Negative (–)
Battery Cable
BATTERY
(Model MGH7000 Only)
Continued

14
MOUNTING BATTERY TO GENERATOR
1. Secure battery to generator by battery hold-down system. This system consists
of the battery mounting bracket, hook bolts, and nut (see Figure 10).
2. Locate the red, positive (+) battery cable from starter solenoid. Connect it to
the positive (+) battery terminal (see Figure 11).
3. Locate the black, negative (–) battery cable attached to engine block. Connect
it to the negative (–) battery terminal (see Figure 11).
4. Check battery before starting engine. Make sure fluid levels are full. Make sure
battery is charged.
See engine owner’s manual for more information.
Figure 10 - Battery Hold-Down System
TO STARTER
SOLENOID
TO ENGINE
BLOCK
Figure 11 - Connecting Positive and Negative Cables to Battery
Nut
Battery
Hook
Bolt
Battery
Mounting
Bracket
BATTERY
(Model MGH7000 Only)
Continued

15
GENERATOR
GROUNDING WARNING
You must properly earth-ground generator before
starting. This will help guard against deadly electric
shock. Only use grounded plugs with generator.
Only use grounded extension cords. Only use three-
wire or double-insulated power tools.
Grounding generator helps prevent electric shock from a ground fault condition.
Locate ground lug on end of generator housing (see Figure 12). Attach a #10
stranded-copper ground wire to ground lug. Drive grounding point into ground.
Grounding point can be a stake, grounding rod, or pipe. Grounding point should be
copper or brass. Attach ground wire to grounding point. You must supply the
ground wire and grounding point. They do not come with generator. Follow the
National Electrical Code and all state and local codes. Consult your power com-
pany or a licensed electrician.
WARNING
For a grounding point, do not use metal pipe being
used to carry combustible materials or gases.
FUEL
F
Ground Lug
Ground Wire
Alternator
Copper or Brass
Grounding Point
Figure 12 - Grounding Generator (Model MGH4000A Shown)

16
EXTENSION
CORDS
Only use grounded extension cords. Be sure to use extension cord with proper wire
gauge size. See chart below.
Recommended Minimum Wire
Gauges (AWG) for Extension Cords
Ampere AWG for Length of Cord in Feet
Load 50' 100' 150'
2181818
3181818
4161616
5161616
6161614
8161412
10 16 14 12
12 14 14 12
14 14 12 10
16 12 12 10
20 10 10 8
WARNING
Have standby installation performed by a skilled,
licensed electrician. Do not let anyone else wire into
a utility circuit. Personal injury, equipment damage,
or damage to home could occur.
IMPORTANT: This generator will not power your entire home. Most home utility
electric service is more than 60 amps. This will exceed generator output. Only
power needed items during a power outage. Make sure total wattage of electrical
load does not exceed rated wattage of generator.
You can use this generator as a standby power source. During a power outage, the
generator will power selected items in a building. Have generator and additional
wiring installed by a skilled, licensed electrician. This is not a do-it-yourself job.
Follow all local codes.
WARNING
The electrician must install a double-throw transfer
switch. This isolates existing electrical circuits from
the utility power line. If not isolated, generator output
will back-feed into utility power line. This may
electrocute a power company line repair person.
STANDBY
INSTALLATION
TO HOME OR
BUILDING
DETERMINING
ELECTRICAL
LOAD FOR
GENERATOR
You must decide what electrical load your generator can power. Do this before
using generator. Use the following four-step method. It will help you select a load
that is not too large. Make sure total wattage of all electrical loads does not exceed
rated wattage of generator. For rated wattage of your generator, see Specifications,
page 7. Electric motors present a special problem when figuring load. Read Step 3
carefully.
1. Make two lists of items you want powered by generator. List all motors and
motor powered appliances in one. List all lights, small appliances, etc. in the

17
other. For standby service to home or building, only include items you must
power.
2. Enter running watts of each item except motors. The light bulb or appliance
nameplate lists its wattage. Remember, 1KW = 1000 watts.
Note: The name-
plate may not list wattage. It may only list volts and amps. The formula for
finding wattage is: Volts x Amps = Watts. For example: An appliance name-
plate states 3 amps at 120 volts. 3 amps x 120 volts = 360 watts.
3. Electric motors present a special problem. They require up to three-times their
rated wattage to start. Chart 2, below, shows starting watts for different size
motors. For example: an electric motor nameplate states 5 amps at 120 volts. 5
amps x 120 volts = 600 watts running. Multiply this figure by 3. This will
show the starting watts needed. 600 watts x 3 = 1800 watts to start. When
figuring the generator load for motors, you must use the starting watts figure.
Do not use the running watts figure.
Note: Some motors require nearly the
same wattage to run as to start. These items include saws, drills, hair dryers,
and food mixers. See Chart 1 for typical appliance wattage examples.
4. Add watts and starting watts of all items. This total must not be larger than the
rated wattage of your generator. It is a good idea to have up to 25% extra
capacity for future needs or extra equipment.
DETERMINING
ELECTRICAL
LOAD FOR
GENERATOR
Continued
Approximate Starting Watts*
Motor Approximate Universal Repulsion Split
HP Running Motors Induction Capacitor Phase
Rating Watts (small appliance) Motors Motors Motors
1/8 275 400 600 850 1200
1/4 400 500 850 1050 1700
1/3 450 600 975 1350 1950
1/2 600 750 1300 1800 2600
3/4 850 1000 1900 2600 x
1 1000 1250 2300 3000 x
1 1/2 1600 1750 3200 4200 x
2 2000 2350 3900 5100 x
3 3000 x 5200 6800 x
Chart 2
* – Always use starting watts,notrunningwatts,whenfiguringcorrectelectricalload.
x – Motors of higher horsepower are not generally used.
Running Starting
Equipment Watts Watts
Light bulb (100W) 100 100
Radio 150 150
Fan 200 600
Television 400 400
Furnace fan (1/3 hp)
with blower 600 1800
Vacuum cleaner 600 750
Sump pump (1/3 hp) 700 2100
Refrigerator/freezer 800 2400
6" Circular saw 800 1000
Floodlight 1000 1000
Running Starting
Equipment Watts Watts
1/2" Drill 1000 1250
Toaster 1200 1200
Coffee maker 1200 1200
Skillet 1200 1200
14" Chain saw 1200 1500
Water well pump
(1/2 hp) 1000 3000
Hot plate/range
(per burner) 1500 1500
10" Table saw 2000 6000
Water heater
(storage-type) 5000 5000
Typical Electric Appliance Wattages
Chart 1

18
120 VOLTS 120/240 VOLTS
FULL POWER
SELECTOR
120
ONLY 120
240V
RESET
RESET
TEST
RESET
RESET
OPERATION
Figure 13 - Receptacle Locations
120V, 30-Amp
Twist-Lock
120V, 15-Amp GFCI Duplex
Model MGH3000 has only the 120V, 15-amp GFCI duplex receptacle.
120/240V, 20 or
30-Amp Twist-Lock
GENERAL INFORMATION
This generator is not large enough to power your entire home. Do not connect
generator to any existing electrical circuits. Plug items directly into generator
receptacles. Do not exceed amperage rating of receptacles. Only use grounded
cords.
DANGER
Use only in well-vented areas. Make sure area has
plenty of free-moving, fresh, outside air. Never run
generator in an enclosed or confined area. Never run
generator inside occupied building. Engine exhaust
contains poisonous carbon monoxide gas.
Overexposure will cause loss of consciousness
and will lead to death.
WARNING
Never connect generator to any existing electrical
circuits. The generator output will back-feed into the
utility power line. This may electrocute a power
company line repair person. Also, if generator is
powering electrical circuits, the chance of an
electrical fire exists.
Note: We supply the engine owner’s manual with generator. Refer to that manual
for questions concerning engine operation.
USING RECEPTACLE
Note: Do not exceed amperage rating of receptacles. Exceeding rating will trip
receptacle circuit breaker.
Use receptacles properly. Improper use could damage generator. Use only
grounded extension cords. Power only grounded or double-insulated items. Do not
overload receptacles. All generators (except model MGH3000) have the following
receptacles (see Figure 13):
• 120V, 15-amp GFCI duplex receptacle
• 120V, 30-amp twist-lock receptacle
• 120/240V, 20 or 30-amp twist-lock receptacle

19
POWER CORD AND PLUG REQUIREMENTS
120V, 30-amp twist-lock receptacle
• NEMA L5-30P plug
• Three-wire, 30-amp cord
120/240V, 20 or 30-amp twist-lock receptacle
• NEMA L14-20P (20-amp) or L14-30P (30-amp) plug
• Four-wire, 20-amp or 30-amp cord
W
(Neutral)
X
(Hot)
Ground
(Green)
120 Volt
30 Amp
G
WX
L5-30P
Plug
w
G
YX
w
G
YX
120V 120V
Neutral
Ground
Ground
X
(Hot)
W
(Neutral)
Y
(Hot)
Ground
(Green)
L14-30P
Plug
L14-20P
Plug
120V 120V
Neutral
120/240 Volt
20 and 30
Amp
Figure 14 - Cord and Plug Configurations
OPERATION
Continued

20
PRESTART
Operate generator on a firm, dry, and clean surface. The surface must be level.
Protect generator from heavy dust, sand, dirt, rain, or snow. Do not locate genera-
tor near standing water and snow. Make sure area is well-vented.
WARNING
Only responsible adults should use generator. Never
let anyone operate generator without proper instruc-
tions.
Note: Ifoillevelistoolow,oilalertsystemwillkeepenginefromstarting(seeOilAlert
System, page 9). Make sure oil level is full before starting. See Engine Oil, page 11.
Before starting the engine, disconnect all electric loads from generator.
STARTING
IMPORTANT: The engine speed is preset. The throttle is locked in preset posi-
tion. Do not adjust throttle. Preset position lets engine run at 3600 RPM under
load. The engine must maintain 3600 RPM for generator to create correct voltage.
Running engine at lower speeds will damage generator and powered items.
IMPORTANT: Never start generator with electrical loads connected. Start engine
before adding electrical loads.
1. Make sure gasoline tank is full. See Fuel, page 12 for fuel information.
2. Move fuel valve lever to the ON position (see Figure 15).
3. Move choke lever fully to the left (see Figure 15). This closes the choke.
Note: You may not need to close choke if engine is warm or air temperature is
high.
OPERATION
Continued
Fuel Valve Lever (ON Position)
Choke Lever (Closed Position)
Figure 15 - Fuel Valve Lever On, Choke Lever Closed