Generac Power Systems MC4000 User manual

Problems?
Questions?
Before taking your unit
back to the store,
call the generator
helpline at
1-800-270-1408
M-F 8-5 CT
Portable Generator Owner’s Manual
This is the safety alert symbol. It is used to alert you to potential personal injury hazards.
Obey all safety messages that follow this symbol to avoid possible injury or death.
Model No. 9802-1 (4,000 Watt AC Generator) Manual No. 99060 Revision 3 (5/17/2001)
Web: www.generac-portables.com or www.briggsandstratton.com
MC4000

Generac Portable Products MC4000 Generator
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EQUIPMENT
DESCRIPTION
This generator is an engine-driven, revolving field,
alternating current (AC) generator. It was designed to
supply electrical power for operating compatible electrical
lighting, appliance, tool, and motor loads. This manual
contains information for a generator that operates
120 and/or 240 Volt AC, single phase, 60 Hz devices that
require up to 4,000 watts (4.0 kW) of power that pull up
to 33.3 Amps at 120 Volts or 16.7 Amps at 240 Volts.
CAUTION! Do Not exceed the generator’s
wattage/amperage capacity. Add up the rated watts of all
devices you are connecting to generator receptacles at one
time. This total should not be greater than 4,000 watts. In
most cases rated watts of the electrical device can be found
on the device nameplate. If the device nameplate gives only
volts and amps, multiply volts times amps to obtain watts
(volts X amps = watts).
The 4,000 watt generator has the following features:
• 120/240 Volt, 20 Amp locking receptacle and a 120 Volt,
30 Amp locking receptacle.
• 120 Volt, 20 Amp GFCI receptacle.
• 12 Volt DC, 10 Amp receptacle.
• Hour meter
• Low Oil Shutdown: Automatically shuts down the engine
if oil drops below safe operation level.
• Four gallon overhead fuel tank with fuel gauge.
• The generator’s revolving field is driven at about
3,600 rpm by a Generac Power Systems 7.8 h.p. engine.
CAUTION! Do Not tamper with engine
governed speed. High operating speeds are
dangerous and increase risk of personal injury or
damage to equipment. The generator supplies
correct rated frequency and voltage only when
running at proper governed speed. Incorrect
frequency and/or voltage can damage some
connected electrical loads. Operating at excessively
low speeds imposes a heavy load. When adequate
engine power is not available engine life may be
shortened.
SAFETY RULES
This generator set was designed and manufactured for
specific applications. Do Not attempt to modify the unit
or use it for any application it was not designed for. If you
have any questions about your generator’s application, ask
your dealer/distributor or consult the factory.
The manufacturer could not possibly anticipate every
circumstance that might involve a hazard. For that reason
warnings in the manual and warnings on tags or decals
affixed to the unit are not all–inclusive. If you intend to
handle, operate or service the unit by a procedure or
method not specifically recommended by the manufacturer,
first make sure that such a procedure or method will not
render this equipment unsafe or pose a threat to you and
others.
Read this manual carefully and become familiar
with your generator set. Know its applications, its
limitations and any hazards involved.
DANGER! You must isolate the generator from
the electric utility by opening the electrical system’s
main circuit breaker or main switch if this unit is
used for backup power. Failure to isolate the
generator from the power utility may result
in injury or death to electric utility workers
and damage to the generator due to a backfeed
of electrical energy. Whenever unit is providing
backup power, the electric utility must be notified.
DANGER! Generator exhaust gases contain
DEADLY carbon monoxide gas. Carbon
monoxide, if breathed in sufficient
concentrations, can cause unconsciousness or
death. Operate this equipment outdoors where
adequate ventilation is available.
The Emission Control System for this generator is
warranted for standards set by the Environmental
Protection Agency. For warranty information refer to the
engine owner’s manual.
The engine exhaust from this product
contains chemicals known to the State
of California to cause cancer, birth
defects, or other reproductive harm.
WARNING:

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• The generator produces a very powerful voltage that can
cause serious injury or death by electrocution. Never
touch bare wires or receptacles. Never permit a child
or any unqualified person to operate the generator.
•Never handle any kind of electrical cord or device while
standing in water, while barefoot or while hands or feet
are wet. Death or serious injury from electrocution may
result.
• Use a ground fault circuit interrupter (GFCI) in any damp
or highly conductive area (such as metal decking or steel
work).
•Never use worn, bare, frayed or otherwise damaged
electrical cords with the generator. Death, serious injury
and property damage from electrical shock may result.
•Gasoline is highly FLAMMABLE and its vapors
are EXPLOSIVE. Never allow smoking, open
flames, sparks or heat in the vicinity while
handling gasoline. Avoid spilling gasoline on a hot
engine. Comply with all laws regulating storage and
handling of gasoline.
•Do Not overfill the fuel tank. Always allow room for
fuel expansion. If tank is overfilled, fuel can overflow
onto a hot engine and cause a FIRE or an
EXPLOSION.
•Never store a generator with fuel in the tank where
gasoline vapors might reach an open flame, spark or pilot
light (as on a furnace, water heater, clothes dryer). FIRE
or an EXPLOSION may result.
• The unit requires an adequate flow of cooling air for its
continued proper operation. Never operate the unit
inside any room or enclosure where the free flow of
cooling air into and out of the unit might be obstructed.
Allow at least 2 feet of clearance on all sides of generator,
even while operating unit outdoors, or you could damage
the unit. See “Cold Weather Operation” on page 10.
•Never start or stop the unit with electrical loads
connected to receptacles with the connected devices
turned ON. Start the engine and let it stabilize before
connecting any electrical loads. Disconnect all electrical
loads before shutting down the generator.
•Do Not insert any object through cooling slots of the
engine. You could damage the unit or injure yourself.
•Never operate the generator:
in rain; in any enclosed compartment; when connected
electrical devices overheat; if electrical output is lost; if
engine or generator sparks; if flame or smoke is
observed while unit is running; if unit vibrates
excessively.
GROUNDING THE
GENERATOR
The National Electrical Code requires that the frame and
external electrically conductive parts of this generator be
properly connected to an approved earth ground. Local
electrical codes may also require proper grounding of the
unit. For that purpose, a GROUNDING WING NUT is
provided on the generator end (Figure 1).
Generally, connecting a No. 12 AWG (American Wire
Gauge) stranded copper wire to the grounding wing nut
and to an earth-driven copper or brass grounding rod
(electrode) provides adequate protection against electrical
shock. Be careful to keep the grounding wire attached after
connecting the stranded copper wire. However, local codes
may vary widely. Consult with a local electrician for
grounding requirements in your area.
Properly grounding the generator helps prevent electrical
shock if a ground fault condition exists in the generator or
in connected electrical devices. Proper grounding also helps
dissipate static electricity, which often builds up in
ungrounded devices.
Figure 1 — Grounding Wing Nut
Grounding
Wing Nut

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12 Volt DC, 10 Amp Receptacle — Use this receptacle
with battery charge cables to charge a 12 Volt battery.
120 Volt AC, 20 Amp GFCI Receptacle — May be
used to supply electrical power for the operation of
120 Volt AC, 20 Amp, single phase, 60 Hz electrical
lighting, appliance, tool and motor loads.
120 Volt AC, 30 Amp Receptacle — May be used to
supply electrical power for the operation of 120 Volt AC,
30 Amp, single phase, 60 Hz electrical lighting, appliance,
tool and motor loads.
120/240 Volt AC, 20 Amp Receptacle — May be used
to supply electrical power for the operation of 120 and/or
240 Volt AC, 20 Amp, single phase, 60 Hz electrical lighting,
appliance, tool and motor loads.
Circuit Breakers (AC) — Each receptacle is provided
with a circuit breaker to protect the generator against
electrical overload. Breakers are "push to reset" type.
Fuel Shut Off Valve — Controls fuel supply to engine.
Fuel Tank — Capacity of 4 U.S. gallons (15 liters).
Grounding Wing Nut — Provides a tie-point for
connecting the generator frame to earth ground.
Idle Control Switch — The idle control runs the engine
at normal (high) speeds when there is an electrical load
present and runs the engine at idle (low) speeds when a
load is not present. This feature greatly improves fuel
economy, extends the life of the engine, and reduces engine
noise.
Run/Stop Switch — Must be in “Run” position to start
engine. Set to “Stop” to stop a running engine.
KNOW YOUR GENERATOR
Read this owner’s manual and safety rules before operating your generator.
Compare the illustrations with your generator to familiarize yourself with the locations of various controls and
adjustments. Save this manual for future reference.
Circuit Breakers (AC)
Idle Control Switch
Run/Stop Switch
Fuel Shut Off Valve
Fuel Tank
120 Volt AC, 30 Amp
Receptacle
120/240 Volt AC,
20 Amp Receptacle
12 Volt DC, 10 Amp
Receptacle
120 Volt AC, 20 Amp,
GFCI Receptacle Grounding Wing Nut

Generac Portable Products MC4000 Generator
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CONTENTS
Check all contents. If any parts are missing or damaged, call
the generator helpline at 1-800-270-1408. Review “Cold
Weather Operation” on page 8. Shipped with your
generator is:
• Main unit
• 20 Amp and 30 Amp locking plugs
• Spare spark plug and air filter
• Spark plug wrench
• Engine and unit owner’s manual
• Battery charge cables
BEFORE STARTING ENGINE
Add Oil
CAUTION! Any attempt to crank or start the engine
before it has been properly filled with the recommended oil
may result in an engine failure.
To fill your engine with oil:
• Place generator on a level surface.
• Clean area around oil fill and remove oil fill cap.
• Select the oil's viscosity grade and fill engine with oil
following the instructions given in the engine owner’s
manual. Do Not overfill!
• Install oil fill cap.
NOTE: The generator’s revolving field rides on a pre-
lubricated and sealed ball bearing that requires no
additional lubrication for the life of the bearing.
Add Gasoline
WARNING! Explosion Hazard! Never fill fuel
tank indoors. Never fill fuel tank when engine is
running or hot. Do Not light a cigarette or smoke
when filling the fuel tank.
WARNING! Do Not overfill the fuel tank.
Always allow room for fuel expansion.
• Use regular UNLEADED gasoline with the generator
engine. Do Not use premium gasoline. Do Not mix oil
with gasoline.
• Clean area around fuel fill cap, remove cap.
• Slowly add unleaded regular gasoline to fuel tank. Be
careful not to overfill. Allow about 1/2" of tank space for
fuel expansion (Figure 2).
• Install fuel cap and wipe up any spilled gasoline.
IMPORTANT: It is important to prevent gum deposits
from forming in essential fuel system parts such as the
carburetor, fuel filter, fuel hose or tank during storage.
Also, experience indicates that alcohol-blended fuels (called
gasohol, ethanol or methanol) can attract moisture, which
leads to separation and formation of acids during storage.
Acidic gas can damage the fuel system of an engine while in
storage.
To avoid engine problems, the fuel system should be
emptied before storage of 30 days or longer. See “Storage”
on page 11. Never use engine or carburetor cleaner
products in the fuel tank as permanent damage may occur.
Figure 2 — Typical Fuel Expansion Space

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OPERATING THE
GENERATOR
CAUTION! Never start or stop the engine with
electrical loads connected to the unit and with the
connected devices turned ON.
Starting the Engine
Disconnect all electrical loads from the generator. Use the
following start instruction steps by numerical order:
1. Make sure the Idle Control switch is in “Off” position.
2. Turn the fuel valve to the “On” position (Figure 3).
3. Set the Run/Stop switch to “Run” position (Figure 4).
4. Place the choke lever in the “Full” choke position
(Figure 5).
5. Grasp the recoil handle and pull slowly until slight
resistance is felt. Then pull rapidly one time only to
start engine.
• If engine starts, proceed to step 7.
• If engine fails to start, proceed to step 6.
6. Move the choke lever to “Half” choke position, and
pull recoil handle twice.
• If engine fails to start, repeat steps 4 thru 6.
7. Move choke lever to “Run” position. If engine falters,
move choke lever to “Half” choke position until the
engine runs smoothly, and then to “Run” position.
NOTE: If engine still fails to start after 3 pulls, check for
proper oil level in crankcase. This unit is equipped with a
Low Oil Shutdown System. See engine manual.
Connecting Electrical Loads
• Let engine stabilize and warm up for a few minutes after
starting.
• Plug in and turn on the desired 120 and/or 240 Volt AC,
single phase, 60 Hertz electrical loads.
•Do Not connect 240 Volt loads to 120 Volt receptacles.
•Do Not connect 3–phase loads to the generator.
•Do Not connect 50Hz loads to the generator.
•DO NOT OVERLOAD THE GENERATOR. Add up
the rated watts (or amps) of all loads to be connected at
one time. This total should not be greater than the rated
wattage/amperage capacity of the generator. See “Don’t
Overload the Generator” on page 11.
Stopping the Engine
• Unplug all electrical loads from generator panel
receptacles. Never start or stop engine with electrical
devices plugged in and turned on.
• Put the Idle Control switch in the “Off” position.
• Let engine run at no–load for 30 seconds to stabilize the
internal temperatures of engine and generator.
• Move Run/Stop switch to “Stop”.
• Close the fuel shut–off valve.
Figure 4 — Run/Stop Switch
“Full” choke
Position
Figure 5 — Choke Lever
Figure 3 — Fuel Valve in Open Position.

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Operating Automatic Idle Control
This switch is designed to greatly improve fuel economy.
When this switch is turned ON, the engine will only
run at its normal high governed engine speed when an
electrical load is connected. When the load is removed,
the engine will run at a reduced speed. With the switch
OFF, the engine will run at the normal high engine speed.
Always have the switch off when starting and
stopping the engine.
Charging a Battery
WARNING! Storage batteries give off explosive
hydrogen gas while recharging. This explosive
mixture will remain around the battery for a long
time after it has been charged. The slightest spark
can ignite the hydrogen and cause an explosion. Such
an explosion can shatter the battery and cause
blindness or other serious injury.
WARNING! Do Not permit smoking, open
flame, sparks or any other source of heat around a
battery. Wear protective goggles, rubber apron and
rubber gloves when working around a battery.
Battery electrolyte fluid is an extremely caustic
sulfuric acid solution that can cause severe burns. If
spill occurs, flush area with clear water immediately.
Your generator has the capability of recharging a discharged
12 Volt automotive or utility style storage battery. Do Not
use the unit to charge any 6 Volt batteries. Do Not use
the unit to crank an engine having a discharged battery.
To recharge 12 Volt batteries, proceed as follows:
• Check fluid level in all battery cells. If necessary, add
ONLY distilled water to cover separators in battery
cells. Do Not use tap water.
• If the battery is equipped with vent caps, make sure they
are installed and are tight.
• If necessary, clean battery terminals.
• Connect battery charge cable connector plug to panel
receptacle identified by the words “12-VOLT D.C.”
• Connect battery charge cable clamp with red handle to
the positive (+) battery terminal (Figure 6).
• Connect battery charge cable clamp with black handle
to the negative (–) battery terminal (Figure 6).
• Start engine. Let the engine run while battery recharges.
• When battery has charged, shut down engine
NOTE: Use an automotive hydrometer to test battery
state of charge and condition. Follow the hydrometer
manufacturer’s instructions carefully. Generally, a battery is
considered to be at 100% state of charge when specific
gravity of its fluid (as measured by hydrometer) is 1.260 or
higher.
Cold Weather Operation
Under certain weather conditions (temperatures below
40°F [4°C] and a high dew point), your Generac generator
may experience icing of the carburetor and/or the
crankcase breather system.
In an emergency, use the original shipping box as a
temporary shelter:
• Cut off all flaps.
• Cut out one of the long sides of the box to expose
exhaust side of unit. Ensure a minimum of two feet
clearance between open side of box and nearest object.
• Cut appropriate slots to access receptacles of unit.
• Start unit, then place box over it.
IMPORTANT: Remove shelter when temperature is
above 40°F [4°C].
For a more permanent shelter, build a structure that will
enclose three sides and the top of the generator:
Figure 6 — Battery Connections

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• Make sure entire muffler-side of generator is exposed
(Figure 7).
• Ensure a minimum of two feet clearance between open
side of box and nearest object.
• Face exposed end away from wind and elements.
• Enclosure should hold enough heat created by the
generator to prevent problems.
CAUTION! NEVER run unit indoors; Do Not
enclose generator any more than shown. Remove
shelter when temperatures are above 40°F [4°C].
RECEPTACLES
120 Volt, 20 Amp GFCI Receptacle
This receptacle (Figure 8) is protected against overload by a
20 Amp, push-to-reset, circuit breaker.
Use each receptacle to operate 120 Volt AC, single-phase,
60 Hz electrical loads requiring up to 2,400 watts (2.4 kW)
at 20 Amps of current. Use cord sets that are rated for
125 Volts at 20 Amps (or greater).
120/240 Volt AC, 20 Amp Locking
Receptacle
Use a NEMA L14-20 plug with this receptacle. Connect a
4-wire cord set rated for 250 Volts at 20 Amps (or greater)
(Figure 9). You can use the same 4-wire cord if you plan to
run a 120 Volt load.
This receptacle powers 120/240 Volt AC, 60 Hz, single
phase loads requiring up to 2,400 watts of power at
20 Amps for 120 Volts; 4,000 watts of power (4.0 kW) at
16.7 Amps for 240 Volts. The outlet is protected by a
20 Amp push-to-reset circuit breaker.
CAUTION! Although the 120/240 Volt outlet
states it has a 240 Volt 20 Amp rating (up to
4,800 watts), the generator is only rated for
4,000 watts. Powering loads that exceed the
wattage/amperage capacity of the generator can
damage it or cause serious injuries. Loads of
240 Volts powered through this outlet should not
exceed 16.7 Amps of current; 120 Volt loads should
not exceed 20 Amps.
Figure 8 — 120 Volt AC, 20 Amp GFCI Receptacle
Figure 9 — 120/240 Volt AC, 20 Amp Receptacle
Figure 7 — Temporary Cold Weather Shelter
Wind

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120 Volt AC, 30 Amp Locking
Receptacle
Use a NEMA L5-30 plug with this receptacle. Connect a
3-wire cord set rated for 125 Volts AC at 30 Amps to the
plug (Figure 10).
Use this receptacle to operate 120 Volt AC, 60 Hz, single
phase loads requiring up to 3,600 watts (3.6 kW) of power
at 30 Amps. The outlet is protected by a 30 Amp
push-to-reset circuit breaker.
12 Volt DC, 10 Amp Receptacle
This connector (identified by the legend “12-VOLT D.C.”)
supplies 12 Volts DC at 10 Amps through battery charging
cables for recharging 12 Volt batteries (Figure 11). See
“Charging a Battery” on page 7.
GROUND FAULT
PROTECTION
This unit is equipped with a Ground Fault Circuit
Interrupter (GFCI). This device meets applicable federal,
state and local codes.
The GFCI protects against electrical shock that may be
caused if your body becomes a path which electricity
travels to reach ground. This could happen if you touch a
“Live” appliance or wire, or are touching plumbing or other
materials that connect to the ground.
When protected by a GFCI, one may still feel a shock, but
the GFCI should cut current off quickly enough so that a
person in normal health should not suffer any serious
electrical injury.
WARNING! The GFCI will not protect you
against the following situations: (1) Line-to-line
shocks; (2) Current overloads or line-to-line short
circuits. The fuse or circuit breaker at the
distribution panel must provide such protection.
Testing the GFCI
Test your GFCI outlet every month, as follows:
• Push the black “Test” button. The red “Reset” button
should pop out, which should allow no power to reach
the outlet. Use a test lamp in each outlet to test this.
CAUTION! If the “Reset” button does not pop
out or the test lamp remains lit when the “Reset”
button is popped out. Do Not use any outlets on
the circuit. Call a qualified electrician.
• If the GFCI tests good, restore power by pressing the
“Reset” button firmly until it is fully in place and locks
in that position. If the GFCI outlet does not reset
properly, Do Not use the outlet — call a qualified
electrician.
• If the GFCI trips by itself at any time, reset and test the
outlet. If the reset button does not pop out when
the test button is pressed, Do Not use the outlet.
Call a qualified electrician.
Figure 10 — 120 Volt AC, 30 Amp Locking Receptacle
Figure 11 — 12 Volt DC, 10 Amp Receptacle

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DON’T OVERLOAD THE
GENERATOR
Overloading a generator in excess of its rated wattage
capacity can result in damage to the generator and/or
connected electrical devices. Observe the following, to
prevent overloading the unit:
• Add up the total wattage of all electrical devices to be
connected at one time. This total should NOT be
greater than the generator’s wattage capacity.
• The rated wattage of lights can be taken from light bulbs.
The rated wattage of tools, appliances and motors can
usually be found on a data plate or decal affixed to the
device.
• If the appliance, tool or motor does not give wattage,
multiply 120 Volts times ampere rating to determine
watts (volts x amps = watts).
• Some electric motors, such as induction types, require
about three times more watts of power for starting than
for running. This surge of power lasts for only a few
seconds when starting such motors. Be sure you allow
for this high starting wattage when selecting electrical
devices to connect to your generator. First estimate the
watts needed to start the largest motor. Add to that
figure the running watts of all other connected loads.
• The wattage reference guide (Figure 12) is provided to
help you to determine how many items the generator
can operate at one time.
Recreational/Home Uses
Tool/Appliance....................................................Watts
AM/FM clock radio.....................................................................50
Light bulb....................................................................................100
Fan................................................................................................200
20" color TV..............................................................................400
*Deep freezer............................................................................500
Personal computer and 15" monitor...................................800
*1/3 hp furnace fan blower.....................................................800
Microwave oven........................................................................800
*18 cu ft refrigerator...............................................................800
Sump pump..............................................................................1000
Electric skillet..........................................................................1250
*½ hp water well pump........................................................1400
*12,000 Btu window air conditioner.................................1400
Space heater............................................................................1800
Electric water heater.............................................................4000
Professional/Contractor Uses
Tool/Appliance....................................................Watts
*1/3 hp airless sprayer.............................................................600
3/8" hammer drill .....................................................................600
Variable speed Sawzall®..........................................................960
½" power drill.........................................................................1000
Quartz-halogen work light...................................................1000
Belt sander...............................................................................1200
7 ¼" circular saw ...................................................................1500
7 ¼" worm drive saw............................................................1600
*1½ hp air compressor ........................................................1800
*10" power miter saw...........................................................1800
6" bench grinder.....................................................................1800
*6" table planer.......................................................................1800
*10" table/radial arm saw .....................................................2000
Wire feed welder...................................................................2400
* allow 3 times listed watts for starting this device
Figure 12 — Wattage Reference Guide

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SPECIFICATIONS
Maximum Surge Watts . . . . . . . . . . . . . . . 5,000 Watts
Continuous Wattage Capacity . . . . . . . . . 4,000 Watts
Power Factor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.0
Rated Maximum Continuous Load Current
At 120 Volts . . . . . . . . . . . . . . . . . . . . . . 33.3 Amps
At 240 Volts . . . . . . . . . . . . . . . . . . . . . . 16.7 Amps
Phase . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-phase
Rated Frequency . . . . . . . . . . . . . . . . . . . . . . 60 Hertz
Fuel Tank Capacity . . . . . . . . . . . . . . . . . 4 U.S. gallons
GENERAL MAINTENANCE
RECOMMENDATIONS
The Owner/Operator is responsible for making sure that
all periodic maintenance tasks are completed on a timely
basis; that all discrepancies are corrected; and that the unit
is kept clean and properly stored. Never operate a
damaged or defective generator.
Engine Maintenance
See engine manual for instructions.
CAUTION! Avoid prolonged or repeated skin
contact with used motor oil. Used motor oil has
been shown to cause skin cancer in certain
laboratory animals. Thoroughly wash exposed areas
with soap and water.
KEEP OUT OF REACH OF CHILDREN. DON'T
POLLUTE. CONSERVE RESOURCES. RETURN
USED OIL TO COLLECTION CENTERS.
Generator Maintenance
Generator maintenance consists of keeping the unit clean
and dry. Operate and store the unit in a clean dry
environment where it will not be exposed to excessive
dust, dirt, moisture or any corrosive vapors. Cooling air
slots in the generator must not become clogged with snow,
leaves or any other foreign material.
NOTE: Do Not use a garden hose or pressure washer to
clean generator. Water can enter engine fuel system and
cause problems. In addition, if water enters generator
through cooling air slots, some of the water will be
retained in voids and cracks of the rotor and stator
winding insulation. Water and dirt buildup on the generator
internal windings will eventually decrease the insulation
resistance of these windings.
To Clean the Generator
• Use a damp cloth to wipe exterior surfaces clean.
• Soft, bristle brush may be used to loosen caked on dirt
or oil.
• A vacuum cleaner may be used to pick up loose dirt and
debris.
• Low pressure air (not to exceed 25 psi) may be used to
blow away dirt. Inspect cooling air slots and opening on
generator. These openings must be kept clean and
unobstructed.
STORAGE INSTRUCTIONS
The generator should be started at least once every seven
days and allowed to run at least 30 minutes. If this cannot
be done and you must store the unit for more than
30 days, use the following guidelines to prepare it for
storage.
Generator Storage
• Clean the generator as outlined in “To Clean the
Generator.”
• Check that cooling air slots and openings on generator
are open and unobstructed.
CAUTION! Storage covers can be flammable. Do
Not place a storage cover over a hot generator. Let
the unit cool for a sufficient time before placing the
cover on the unit.
Engine Storage
See engine owner’s manual for instructions.
Other Storage Tips
•Do Not store gasoline from one season to another.
• Replace your gasoline can if it starts to rust. Rust and/or
dirt in a gasoline can cause problems when you use
contaminated fuel with this unit.
• Store in clean and dry area.

Generac Portable Products MC4000 Generator
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TROUBLESHOOTING
Problem Cause Solution
Engine is running, but
no AC output is
available.
1. Circuit breaker is open.
2. Poor connection or defective cord set.
3. Connected device is bad.
4. Fault in generator.
1. Reset circuit breaker.
2. Check and repair.
3. Connect another device that is in good
condition.
4. Contact Generac service facility.
Engine runs good but
bogs down when loads
are connected.
1. Short circuit in a connected load.
2. Generator is overloaded.
3. Engine speed is too slow.
4. Shorted generator circuit.
1. Disconnect shorted electrical load.
2. See “Don’t Overload the Generator”
on page 10.
3. Contact Generac service facility.
4. Contact Generac service facility.
Engine will not start; or
starts and runs rough.
1. Run/Stop switch set to “Stop”.
2. Dirty air cleaner.
3. Out of gasoline.
4. Stale gasoline.
5. Spark plug wire not connected to spark
plug.
6. Bad spark plug.
7. Water in gasoline.
8. Overchoking.
9. Low oil level.
10. Excessively rich fuel mixture.
11. Intake valve stuck open or closed.
12. Engine has lost compression.
1. Set switch to “Run”.
2. Clean or replace air cleaner.
3. Fill fuel tank.
4. Drain gas tank and fill with fresh fuel.
5. Connect wire to spark plug.
6. Replace spark plug.
7. Drain gas tank; fill with fresh fuel.
8. Put choke lever to “No Choke”
position.
9. Fill crankcase to proper level.
10. Contact Generac service facility.
11. Contact Generac service facility.
12. Contact Generac service facility.
Engine shuts down
during operation.
1. Out of gasoline.
2. Low oil level.
3. Fault in engine.
1. Fill fuel tank.
2. Fill crankcase to proper level.
3. Contact Generac service facility.
Engine lacks power.
1. Load is too high.
2. Dirty air filter.
3. Engine needs to be serviced.
1. See “Don’t Overload the Generator”
on page 10.
2. Replace air filter.
3. Contact Generac service facility.
Engine “hunts” or
falters.
1. Choke is opened too soon.
2. Carburetor is running too rich or too
lean.
1. Move choke to halfway position till
engine runs smoothly.
2. Contact Generac service facility.

Generac Portable Products MC4000 Generator
13
NOTES

Generac Portable Products MC4000 Generator
14
ELECTRICAL SCHEMATIC

Generac Portable Products MC4000 Generator
15
WIRING DIAGRAM

Generac Portable Products MC4000 Generator
16
EXPLODED VIEW – MAIN UNIT

Generac Portable Products MC4000 Generator
17
Item Part # Qty Description
1 93199 1 CRADLE, XL
2 84021 1 SUPPORT, Engine
3 NSP 1 ENGINE
4 66365 1 HOUSING, Engine Adapter
5 84141 1 ASSEMBLY, Rotor
6 83540 1 ASSEMBLY, Stator
7 65791 1 BEARING
8 67451 1 WASHER, M8 Flat
10 86307 4 HHMS, 5/16-24 x 3/4
11 47480 1 HHCS, 5/16-24 x 7"
12 84508 2 MOUNT, Vibration 45°
14 83208 1 BRACKET, Muffler
15 B4986 1 DECAL, Ground
16 66476 2 HHMS, LW M6 1.00 x 12
17 89476 1 GASKET, Exhaust
18 70644 1 PPHMS, M8 1.25 x 20
19 84346 3 PPHMS, M8 x 35
20 40976 2 SHCS, M8 1.25 x 20
21 83083 1 SCREEN, Spark Arrest
22 83071 1 MUFFLER
23 81917 1 PIN, Roll M4 x 10
25 66825B 1 CARRIER, Rear Bearing
26 85652 2 MOUNT, Vibration
27 67989 10 NUT, M8 Flanged Serrated
30 74908 4 TAPTITE, M5-0.8 x 10
32 86308 4 BOLT, M6 - 1.0 x 115
33 65795 1 RECTIFIER, Battery Charge
34 66849A 1 TAPTITE, M5 0.8 x 20
35 67022 1 GROMMET, Rubber
36 84132 1 ASSMBLY, Drive Module Pwr
Reg.
37 66386 1 ASSEMBLY, Brush Holder
38 66849 2 TAPTITE, M5 0.8 x 16
39 67025 1 COVER, Bearing Carrier
Item Part # Qty Description
41 86494 1 SCREW, M6 -1.0 x 16 Wing
42 86292 5 HHCS, 10 - 16 x Self Driller
43 77395 4 NUT, M6 Flange Lock
44 83465 4 GROMMET, Tank
46 78831B 4 HHMS, M6 1.0 x 60 (blk)
47 80270 1 VALVE, Tank
48 78299 1 BUSHING, Plastic Tank
49 85134 1 CAP, Fuel
50 88325 1 TANK, Fuel
51 84042 1 SHIELD, Heat
52 84687 1 INSULATION, #2-1/4" Thick
53 85000 1 CLIP, Insulation
54 14353621 1 WIRE, Ground
55 23762 1 WASHER, Shakeproof #10
56 26850 2 WASHER, M6 Shakeproof
61 92982 1 DECAL, Danger
62 92782 2 DECAL, Heat Shield
67 93221 2 DECAL, Cradle
68 93826 1 DECAL, Start Instructions
69 84409 1 SLEEVING, Flexo 1/2" X .83 ft.
Parts Not Illustrated:
37806 120 Volt AC 30 Amp Plug
43483 120/240 Volt AC 20 Amp Plug
65787 Battery Charge Cable
72347 Spark Plug
78601 Air Filter
84882 Spark Plug Wrench
99060 Owner’s Manual
NSP Engine Owner’s Manual
Optional Accessories Not Included:
84883 Cord Wrap
84895 Storage Cover
PARTS LIST – MAIN UNIT

Generac Portable Products MC4000 Generator
18
EXPLODED VIEW AND PARTS LIST – CONTROL PANEL
Item Part # Qty. Description
1 92811 1 PANEL, Control
2 75475 6 SCREW, .7 X 10mm
3 22264 6 WASHER, M4 Lock
4 38150 6 WASHER, Flat
5 51715 6 NUT, M4 Hex
6 80409 1 RECEPTACLE, Dplx GFCI 20A
7 68867 1 OUTLET, 120/240 Volt, 20 Amp
Locking
8 77604 1 METER, Hour
9 68868 1 OUTLET, 120 Volts, 30 Amp
Locking
10 82538 1 SWITCH, On/Off Rocker
11 43181 8 SCREW, .5 X 10mm
12 43182 8 WASHER, M3 Lock
13 66822 1 OUTLET, 12 Volt DC
14 75207 2 CIRCUIT BREAKER, 20 Amp
Item Part # Qty. Description
15 82881 3 WASHER, Internal Lock
16 75207A 1 CIRCUIT BREAKER, 30 Amp
17 84028 1 TRANSFORMER, Idle Control
18 64525 4 STANDOFF, ¾" Hex
19 64526 8 SCREW, 32 X 3/8"
20 83970 1 CONTROL BOARD, System
21 84335 1 WIRE HARNESS
22 87692 1 CIRCUIT BREAKER, 10 Amp
23 84134 1 GROMMET, Rubber
24 87782 1 BOX, Control
25 91526 4 SCREW, .8 x 12mm
26 49226 4 WASHER, M5 Lock
27 23897 4 WASHER, M5 Flat
29 51714 2 NUT, M3 Hex
30 23365 6 WASHER, Shakeproof

Generac Portable Products MC4000 Generator
19
NOTES

LIMITED WARRANTY
FOR "GN" ENGINE DRIVEN PORTABLE GENERATORS
GENERAC PORTABLE PRODUCTS (hereafter referred to as the COMPANY) warrants to the original purchaser that the
alternator and control panel for its portable generator will be free from defects in materials or workmanship for the items
and period set forth below from the date of original purchase. This warranty is not transferable and applies only to portable
generators driven by a GN-Series engine.
Consumer* Commercial*
Alternator 2 years (2nd year parts only) 1 year
Engine Warranted solely by the engine manufacturer
With the exception of European Community Countries, all units bound for export shall be warranted for One (1)
Year in Consumer applications, and 90 days in Commercial applications as defined below.
*NOTE: For the purpose of this warranty "consumer use" means personal residential household use by
original purchaser. This warranty does not apply to units used for Prime Power in place of utility.
"Commercial Use" means all other uses, including rental, construction, commercial and income producing
purposes. Once a generator has experienced commercial use, it shall thereafter be considered a
commercial use generator for the purposes of this warranty.
During said warranty period, the COMPANY will, at is option, repair or replace any part which, upon examination by the
COMPANY, is found to be defective under normal use and service**. Starting batteries are not warranted by the
COMPANY. All transportation costs under warranty, including return to the factory if necessary, are to be borne by the
purchaser and prepaid by the purchaser. This warranty does not cover normal maintenance and service and does not apply
to a generator set, alternator, or parts which have been subjected to improper or unauthorized installation or alteration,
misuse, negligence, accident, overloading, overspeeding, improper maintenance, repair or storage so as, in the COMPANY’s
judgement, to adversely affect its performance and reliability.
**NORMAL WEAR: As with all mechanical devices, the generator need periodic parts service and
replacement to perform well. This warranty will not cover repair when normal use has exhausted the life of
a part or generator.
THERE IS NO OTHER EXPRESS WARRANTY. THE COMPANY HEREBY DISCLAIMS ANY AND ALL
IMPLIED WARRANTIES, INCLUDING BUT NOT LIMITED TO THOSE OF MERCHANTABILITY AND
FITNESS FOR A PARTICULAR PURPOSE TO THE EXTENT PERMITTED BY LAW. THE DURATION OF
ANY IMPLIED WARRANTIES WHICH CANNOT BE DISCLAIMED IS LIMITED TO THE TIME PERIOD AS
SPECIFIED IN THE EXPRESS WARRANTY. LIABILITY FOR CONSEQUENTIAL, INCIDENTAL OR SPECIAL
DAMAGES UNDER ANY AND ALL WARRANTIES IS EXCLUDED. THE COMPANY ALSO DISCLAIMS
ANY RESPONSIBILITY FOR INCIDENTAL OR CONSEQUENTIAL DAMAGES, SUCH AS THE LOSS OF
TIME OR THE USE OF THE POWER EQUIPMENT, OR ANY COMMERCIAL LOSS DUE TO THE FAILURE
OF THE EQUIPMENT: AND ANY IMPLIED WARRANTIES ARE LIMITED TO THE DURATION OF THIS
WRITTEN WARRANTY.
Some states do not allow limitations on how long an implied warranty lasts, or the exclusion or limitation of incidental or
consequential damages, so the above limitations or exclusions may not apply to you. This warranty gives you specific legal
rights and you may also have other rights, which vary from state to state.
For service, see your nearest COMPANY authorized warranty service facility or call 1-877-544-0982. Warranty service can
be performed only by a COMPANY authorized service facility. This warranty will not apply to service at any other facility.
At the time of requesting warranty service, evidence of original purchase date must be presented.
GENERAC PORTABLE PRODUCTS
Jefferson, Wisconsin 53549