Kohler PRO 3.7, PRO 5.2, PRO 7.5 Owner's Manual

37 590 01 Rev. F

KohlerPower.com

PRO 3.7, PRO 3.7 E, PRO 5.2, PRO 5.2 E,
PRO 7.5, PRO 7.5 E

Generator Owner's Manual

IMPORTANT: Read all safety precautions and instructions carefully before

operating equipment.

Ensure engine is stopped and level before performing any

maintenance or service.

Record product information to reference when ordering parts or obtaining warranty coverage.

Specifi cation
Serial Number
Purchase Date

EN

ESS

FRC

2 37 590 01 Rev. FKohlerPower.com

California Proposition 65 Warning

Engine exhaust from this product contains chemicals known
to State of California to cause cancer, birth defects, or other
reproductive harm.

WARNING

Explosive Fuel
can cause fi res
and severe
burns.

Do not fi ll fuel
tank while
engine is hot or
running.

Gasoline is extremely
fl ammable and its vapors
can explode if ignited.
Never refuel while smoking
or in vicinity of an open
fl ame. Store gasoline only
in approved containers, in
well ventilated, unoccupied
buildings, away from sparks
or fl ames. Spilled fuel
could ignite if it comes in
contact with hot parts or
sparks from ignition. Never
use gasoline as a cleaning
agent.

WARNING

Rotating Parts
can cause
severe injury.

Stay away while
generator is in
operation.

Keep hands, feet, hair,
and clothing away from all
moving parts to prevent
injury. Never operate
generator with covers,
shrouds, or guards
removed.

WARNING

Hot Parts can
cause severe
burns.

Do not touch
generator while
operating or just
after stopping.

Never operate generator
with heat shields or guards
removed. Do not modify
generator.

Place generator in a place
where pedestrians or
children are not likely to
touch generator.

Be sure to carry generator
only by its carrying handles.

WARNING

Hazardous
Voltage.

Backfeed to
utility system
can cause
property
damage, severe
injury, or death.

Never plug a portable
generator directly into a
building outlet.

If generator is used for
standby power, have a
certifi ed, licensed electrician
install an automatic
transfer switch to prevent
inadvertent interconnection
of standby and normal
sources of supply.

CAUTION

Electrical Shock
can cause injury.

Do not touch
wires while
generator is
running.

Never operate generator in
rain or snow.

Never touch generator
with wet hands or electrical
shock may occur.

WARNING

Accidental
Starts can cause
severe injury or
death.

Disconnect and
ground spark
plug lead(s)
before servicing.

Before working on
generator or equipment,
disable engine as follows:

1) Disconnect spark plug
lead(s). 2) Disconnect
negative (–) battery cable
from battery.

Do not allow children to
operate generator.

Safety Precautions

DANGER: A hazard that will result in death, serious injury, or substantial property damage.

WARNING: A hazard that could result in death, serious injury, or substantial property damage.

CAUTION: A hazard that could result in minor personal injury or property damage.

NOTE: is used to notify people of important installation, operation, or maintenance information.
Read this manual carefully before operating this machine. This manual should stay with this

machine if it is sold.

California Proposition 65 Warning

This product contains chemicals known to State of California
to cause cancer, birth defects, or other reproductive harm.

3

37 590 01 Rev. F

KohlerPower.com

EN

Important Labels on Generator

WARNING /

ADVERTENCIA / AVERTISSEMENT

Ɣ Hot parts can cause severe burns. / Las piezas calientes pueden causar quemaduras graves. / Les pièces chaudes peuvent causer de graves brûlures.

Ɣ Do not touch generator while operating or just after stopping. / No toque el generador durante el funcionamiento o inmediatamente después de pararse. / Ne touchez pas le générateur pendant qu'il tourne ou si

vous venez tout juste de l'arrêter.

Ɣ Explosive Fuel can cause fires and severe burns. / La explosión del carburante puede provocar incendios y quemaduras graves. / Carburant explosif pouvant causer des incendies et des brûlures graves.
Ɣ Do not fill fuel tank while generator is hot or running. / No llene el tanque de combustible mientras el generador esté caliente o funcionando. / N'ajoutez pas de carburant si le moteur est chaud ou s'il tourne.

Ɣ Electrical shock can cause injury. / Las descargas eléctricas pueden provocar lesiones. / Les chocs électriques peuvent causer des blessures.
Ɣ Do not touch wires while generator is running. / No toque los cables con el generador en funcionamient. / Ne touchez pas aux le générateur pendant que le moteur tourne.
Ɣ Do not connect generator to a building's electrical system unless using an isolation (transfer) switch installed by a certified, licensed electrician. / No conecte el generador al sistema eléctrico de un edificio a menos

que use un aislamiento (transferencia) interruptor instalado por un electricista certificado y certificado. / Ne branchez pas le générateur dans le système électrique d’un bâtiment sauf si un commutateur-converteur
a été installé par un électricien agréé et compétent.

DANGER

Using a generator indoors CAN KILL YOU IN MINUTES.
Generator exhaust contains carbon monoxide.
This is a poison you cannot see or smell.

NEVER use inside a home
or garage, EVEN IF doors
and windows are open.

Only use OUTSIDE and far
away from windows, door,
and vents.

Avoid other generator hazards.

READ MANUAL BEFORE USE.

4 37 590 01 Rev. FKohlerPower.com

B

C

K

L

D

EEE E

U

V

E F

H

T

W

GG

J

Y Z

AC

AD

AA

AE

AB

O

R

P

Q

X

N

S

M

I

A

A Circuit Breaker B

Maintenance

Minder

C

240/120V/30A

Electrical Socket

D

120V/30A

Electrical Socket

E Circuit Protector F

12V DC

Receptacle

3

G GFCI Receptacle H Ground Terminal

I Auto Idle

3

J

On/Off/Start

Switch

K Fuel Tank Cap L

Fuel Level

Indicator

M Oil Drain Plug N

Oil Fill Plug/

Dipstick

O Starter Battery

3

P Choke Lever

Q Spark Plug R Carbon Canister2S Starter Handle T Screw
U Air Cleaner Cover V Foam Element W Base X Fuel Valve

Y Change Oil Light Z

Replace Spark

Plug Light

AA

Replace Air

Cleaner Light

AB

Low Oil

Indicator Light

AC Reset AD Fuel Filter AE Voltage Selector

1

1

PRO 3.7, PRO 3.7 E, PRO 5.2 and PRO 5.2 E only. 2California only. 3Electric start models only.

5

37 590 01 Rev. F

KohlerPower.com

EN

Pre-Start Checklist

1. Ensure generator is at least 3.3 ft. (1 m) from
building or other equipment and not covered
with any material.

2. Refer to all warning labels prior to starting.

3. Check oil level using oil fi ll plug (N). Add oil if
low. Do not overfi ll.

4. Check fuel level indicator (L). Add fuel if low.
Stop refueling when indicator reaches F (full)
level. Check fuel system components and
lines for leaks. Never refuel while unit is
running.

5. Test GFCI receptacle (G).

6. Check that air cleaner components and all air
inlets are unobstructed, equipment covers,
and guards are in place and securely
fastened.

7. Ensure electrical devices (load) are not
connected to generator.

Starting

WARNING

Rotating Parts can cause severe
injury.

Stay away while engine is in
operation.

Keep hands, feet, hair, and clothing away
from all moving parts to prevent injury. Never
operate engine with covers, shrouds, or
guards removed.

NOTE: Auto Idle (I) switch must be in OFF

position when using electric devices
that require a large starting current,
such as a compressor or a submersible
pump. Auto Idle (I) controls engine
speed according to connected load.
Results are better fuel consumption
and less noise.

NOTE: Choke is not required to start a warm

engine. Push choke lever (P) in to
original position.

1. Turn main AC circuit breaker (A) OFF.

2. Turn Auto Idle (I) OFF (if equipped).

3. Turn Fuel (X) ON.

4. Turn engine to ON (J) and pull rope (or push
start button (J) for electric start).

5. Turn choke lever (P) OFF after engine is
warm.

If engine does not start, repeat operation until
engine starts by gradually opening choke.

Cold Weather Starting

1. Use proper oil for temperature expected.

2. Disengage all possible external loads.

3. Use fresh winter grade fuel. Winter grade
fuel has higher volatility to improve starting.

Operation

WARNING

Hazardous Voltage.
Backfeed to utility system can

cause property damage, severe
injury, or death.

Never plug a portable generator directly into
a building outlet.

If generator is used for standby power,
have a certifi ed, licensed electrician install
an automatic transfer switch to prevent
inadvertent interconnection of standby and
normal sources of supply.

When running speed of generating set has
stabilized (approximately 3 minutes):

1. Check that circuit protectors (E) are pushed
in. Press if necessary.

2. Connect appliances to electrical sockets (C,
D & G) of generator.

3. Maintenance Minder (B) shows number of
hours that generator has worked.

Angle of Operation

Do not operate this engine exceeding maximum
angle of operation; see specifi cation table.
Engine damage could result from insuffi cient
lubrication.

6 37 590 01 Rev. FKohlerPower.com

Cable Selection

Generator

Socket Type

10 A 16 A 32 A

Recommended

Cable Cross

Section

mm

2

AWG

mm

2

AWG

mm

2

AWG

Length

of

Cable

Used

0 to

50 m

4106 9107

51 to

100 m

10 7 10 7 25 3

101 to

150 m

1

10 7 16 5 35 2

1

This cable length is maximum permitted

length, and must not be exceeded.
Installation method=cables on raceway

or non-drilled tablet/Permitted drop in
voltage=5%/Multi-core conductors/Cable
type PVC 70°C (e.g. H07RNF)/Ambient
temperature=86° F (30° C).

ON/OFF/START Switch

ON/OFF/START switch (J) controls ignition
system.

ON Position:
Ignition circuit is switched on. Engine can be

started.
OFF Position:
Ignition circuit is switched off. Engine will not

run.
START Position:
Pressing and holding switch in START

position will start engine with electric start (if

equipped).

Auto Idle

When Auto Idle (I) switch is in ON position,
Auto Idle (I) controls engine speed according
to connected load. Results are better fuel
consumption and less noise.

When Auto Idle (I) switch is in OFF position,
engine runs at rated rpm (3,600 rpm)
regardless of whether there is a load connected
or not.

Stopping

1. Disconnect plugs from electrical sockets (C,
D, F & G) to let engine run under no load for
1 or 2 minutes.

2. Set ON/OFF/START switch (J) to OFF
position: generator stops.

3. Close fuel valve (X).

High Altitude Operation

This generator may require a high altitude
carburetor kit to ensure correct engine
operation at altitudes above 4000 ft. (1219
meters). To obtain high altitude kit information
or to fi nd a Kohler portable dealer go to
KohlerPower.com or call 1-800-544-2444.

This generator should be operated in its original
confi guration below 4000 ft. (1219 meters) as
damage may occur if high altitude carburetor
kit is installed and operated below 4000 ft.
(1219 meters).

Engine Speed

NOTE: Do not tamper with governor setting to

increase maximum engine speed.
Overspeed is hazardous and will void
warranty.

7

37 590 01 Rev. F

KohlerPower.com

EN

Maintenance Instructions

WARNING

Before working on engine or equipment, disable
engine as follows: 1) Disconnect spark plug
lead(s). 2) Disconnect negative (–) battery cable
from battery.

Accidental Starts can cause
severe injury or death.

Disconnect and ground spark
plug lead(s) before servicing.

Safety is an obligation of owner. Periodic inspection, adjustment and lubrication will keep your
generator in safest and most effi cient condition possible. Most important points of generator
inspection, adjustment, and lubrication are explained on following pages.

Maintenance Schedule

After fi rst 5 Hours

● Change oil.
Every 25 Hours or Annually

● Check starter battery (O).
Every 100 Hours or Annually

1

● Clean low-profi le air cleaner element (V).

● Change oil.

● Clean cooling areas.
Every 200 Hours

2

● Check and adjust valve clearance when engine is cold.
Every 300 Hours

● Replace low-profi le air cleaner element (V).

● Check fuel fi lter (AD) and clean or replace if needed.
Every 500 Hours or Annually

1

● Replace spark plug and set gap.

1

Perform these procedures more frequently under severe, dusty, dirty conditions.

2

Have a Kohler portable dealer perform this service.

Oil Recommendations

We recommend use of Kohler oils for best
performance. Other high-quality detergent
oils (including synthetic) of API (American
Petroleum Institute) service class SJ or higher
are acceptable. Select viscosity based on air
temperature at time of operation as shown in
table below.

°F

-20

020324060

50 80 100

°C

-30 -20

-10 0

10 20 30

40

5W-30

10W-30

SAE 30

Check Oil Level

NOTE: To prevent extensive engine wear or

damage, never run engine with oil level
below or above operating range
indicator on dipstick (N).

Ensure engine is cool. Clean oil fi ll/dipstick (N)
areas of any debris.

1. Remove oil fi ll/dipstick (N); wipe oil off.

2. Remove oil fi ll/dipstick (N); check oil level.
Level should be at top of indicator on dipstick
(N).

3. If oil is low, add oil up to point of overfl owing
fi ller neck.

4. Reinstall oil fi ll/dipstick (N) and tighten
securely.

Change Oil

When change oil light (Y) goes on, press reset
(AC) and follow maintenance instructions.
Change oil while engine is warm.

1. Clean area around oil fi ll cap/dipstick (N) and
oil drain plug (M).

2. Remove oil drain plug (M) and oil fi ll cap/
dipstick (N). Drain oil completely.

3. Reinstall oil drain plug (M). Torque to
13 ft. lb. (17.6 N·m).

4. Fill crankcase with new oil, up to point of
overfl owing fi ller neck.

5. Reinstall oil fi ll cap/dipstick (N) and tighten
securely.

6. Dispose of used oil in accordance with local
ordinances.

8 37 590 01 Rev. FKohlerPower.com

Fuel Level

WARNING

Explosive Fuel can cause fi res
and severe burns.

Do not fi ll fuel tank while
generator is hot or running.

Gasoline is extremely fl ammable and
its vapors can explode if ignited. Store
gasoline only in approved containers, in
well ventilated, unoccupied buildings, away
from sparks or fl ames. Spilled fuel could
ignite if it comes in contact with hot parts or
sparks from ignition. Never use gasoline as a
cleaning agent.

Visually check level of fuel. If necessary, fi ll up.

1. Unscrew fuel tank cap (K).

2. Fill tank until fuel gauge shows F, using

funnel and taking care not to spill any fuel.

3. Screw down fuel tank cap (K) tightly.

Fuel Line

Low permeation fuel line must be installed on
carbureted Kohler Co. engines to maintain EPA
and CARB regulatory compliance.

Fuel Filter

1. Open fuel tank cap (K).

2. Remove fuel fi lter (AD) from tank neck.

3. Clean fuel fi lter (AD) with a non-fl ammable

solvent or solvent with a high fl ash point. Dry
it fully. Replace as necessary.

4. Reinstall fuel fi lter (AD).

5. Reinstall fuel tank cap (K).

Sediment Bowl

1. Close fuel valve (X) and remove cover

screws and nuts.

2. Remove cover.

3. Remove sediment bowl.

4. Clean sediment bowl with a non-fl ammable

solvent or solvent with a high fl ash point. Dry
it fully.

5. Check sediment bowl cover and gasket.

Replace them if they are damaged.

6. Reinstall sediment bowl.

7. Open tank fuel valve (X).

8. Wipe off any trace of fuel with a clean cloth

and check for any leakage.

Oil Sentry™ (if equipped)

This switch is designed to prevent engine
from starting in a low oil or no oil condition. Oil
Sentry™ may not shut down a running engine
before damage occurs.

Fuel Recommendations

WARNING

Explosive Fuel can cause fi res
and severe burns.

Do not fi ll fuel tank while engine is
hot or running.

Gasoline is extremely fl ammable and its
vapors can explode if ignited. Never refuel
while smoking or in vicinity of an open fl ame.
Store gasoline only in approved containers,
in well ventilated, unoccupied buildings, away
from sparks or fl ames. Spilled fuel could
ignite if it comes in contact with hot parts or
sparks from ignition. Never use gasoline as a
cleaning agent.

NOTE: E15, E20 and E85 are NOT approved

and should NOT be used; effects of
old, stale or contaminated fuel are not
warrantable.

Fuel must meet these requirements:

● Clean, fresh, unleaded gasoline.

● Octane rating of 87(R+M)/2 or higher.

● Research Octane Number (RON) 90 octane

minimum.

● Gasoline up to 10% ethyl alcohol, 90%
unleaded is acceptable.

● Methyl Tertiary Butyl Ether (MTBE) and
unleaded gasoline blend (max 15% MTBE by
volume) are approved.

● Do not add oil to gasoline.

● Do not overfi ll fuel tank.

● Do not use gasoline older than 30 days.

9

37 590 01 Rev. F

KohlerPower.com

EN

Air Cooling

WARNING

Hot Parts can cause severe
burns.

Do not touch generator while
operating or just after stopping.

Never operate generator with heat shields or
guards removed. Do not modify generator.

Place generator in a place where pedestrians
or children are not likely to touch generator.

Be sure to carry generator only by its
carrying handles.

Proper cooling is essential. To prevent over
heating, ensure air cooling inlet and outlet
areas are clean and unobstructed. Avoid
spraying water at wiring harness or any
electrical components. Refer to Maintenance
Schedule.

Ground Terminal

Ground terminal (H) connects earth line for
prevention of electric shock. When electric
device is grounded, be sure to ground
generator also.

Connect generator to ground: Attach a 6 AWG
(10 mm2) copper wire to generator’s ground
connection and to a galvanized steel grounding
rod (not provided) driven 3.3 ft. (1 m) into
ground.

Connecting Alternating Current (AC)

NOTE: Ensure all electric devices including

lines and plug connection are in good
condition before connection to
generator.

NOTE: Ensure total load is within generator

rated output.

NOTE: Ensure receptacle load current is within

receptacle rated current.

1. Start engine.

2. Plug into AC receptacle (C, D or G).

3. Turn on any electric devices.

AC Rated Power

AC rated power is maximum amount of power
generator can support.

AC Maximum Power

AC maximum power is additional power
generator momentarily produces to aid in
starting of electrical devices requiring power
above generator's rated power requirements.

Spark Plugs

CAUTION

Electrical Shock can cause injury.
Do not touch wires while

generator is running.

Never operate generator in rain or snow.
Never touch generator with wet hands or

electrical shock may occur.

When replace spark plug light (Z) goes on,
press reset (AC) and follow maintenance
instructions.

Clean out spark plug recess. Remove spark
plug (Q) and replace.

1. Check gap using wire feeler gauge. Adjust
gap, see specifi cation table for adjustment.

2. Install spark plug (Q) into cylinder head.

3. Torque spark plug (Q) to 20 ft. lb. (27 N·m).

Air Cleaner

NOTE: Operating engine with loose or

damaged air cleaner components
could cause premature wear and
failure. Replace all bent or damaged
components.

When replace air cleaner light (AA) goes on,
press reset (AC) and follow maintenance
instructions.

1. Remove screw (T) and air cleaner cover (U).

2. Remove foam element (V) from air cleaner
base (W).

3. Wash foam element (V) in warm water with
detergent. Rinse and allow to air dry.

4. Lightly oil foam element (V) with new engine
oil; squeeze out excess oil.

5. Reinstall foam element (V) into air cleaner
base (W).

6. Reinstall cover and secure with screw (T).

Breather Tube

Ensure both ends of breather tube are properly
connected.

10 37 590 01 Rev. FKohlerPower.com

GFCI Receptacle

CAUTION

Electrical Shock can cause injury.
Do not touch wires while

generator is running.

Never operate generator in rain or snow.
Never touch generator with wet hands or

electrical shock may occur.

To reduce chance of electrical shock:

1. Do not attempt to operate equipment if

ground fault circuit interrupter (GFCI) RESET
button pops out repeatedly during use.

2. Remember that only receptacles labeled

GFCI have ground fault circuit interrupter
protection.

Ground Fault Circuit Interrupter (GFCI) stops
power to protected receptacles (G) if a ground
fault (electrical leak) is detected. If RESET
button pops out, equipment plugged into
receptacle (G) may be faulty. If this happens,
check equipment carefully. If equipment
appears to be in good condition, press RESET
button fi rmly until a click is heard. This will
restore power. If RESET button pops out again,
unplug equipment immediately. Contact a
Kohler portable dealer before attempting to use
it again.

GFCI Receptacle Test

1. Start engine.

2. Press TEST button, if functioning properly

RESET button should pop out, stopping
power to outlet.

3. If GFCI operation is correct, push RESET

button in. If GFCI operates incorrectly,
contact a Kohler portable dealer.

Overload (Capacity of Generator)

Never exceed rated load of generator (in Amps
and/or Watts) when it is running continuously.
See specifi cations table for rated outputs.

Before connecting and operating generator,
calculate electrical power required by electric
appliances (in Watts). This electrical power
rating is usually found on manufacturer's
plate on bulbs, electrical appliances, motors,
etc. Sum total of power required by these
appliances should not exceed nominal power
rating of generator.

Circuit protectors (E) and circuit breaker (A) will
stop power to protected receptacles (C, D, F or
G) when an overload of a connected electrical
device is detected or AC output voltage rises to
protect generator and any connected electric
devices.

When overload occurs and power generation
stops, proceed as follows:

1. Turn off any connected electric devices and
stop generator.

2. Reduce total wattage of connected electric
devices within application range.

3. Check for blockages in cooling air inlet and
outlet areas and around control unit. If any
blockages are found, remove them.

4. After checking, restart generator.

Voltage Selector (if equipped)

When voltage selector (AE) switch is in
120V/240V position, 120V is supplied to all
electrical sockets (C, D & G) and 240V is
supplied to 240/120V/30A electrical socket (C).
When voltage selector (AE) switch is in 120V
position, only 120V is supplied to electrical
sockets (D & G).

Ensure to turn main circuit breaker (A) to
OFF position before using voltage selector
(AE) switch to avoid accidentally damaging
generator because of any connected load that
may be drawing power from unit.

Voltage Selector Receptacle Power

Switch
Position Receptacle

Available Power

PRO 3.7

PRO 3.7 E

PRO 5.2

PRO 5.2 E

120V
Only

240V/120V/
30A

25A @

120V

30A @

120V

120V/30A

25A @

120V

30A @

120V

GFCI

20A @

120V

20A @

120V

120V/
240V

240V/120V/
30A

12.5A/
240V

18.5A/
240V

120V/30A

12.5A/
120V

18.5A/
120V

GFCI

12.5A/
120V

18.5A/
120V

11

37 590 01 Rev. F

KohlerPower.com

EN

Battery Charging Using DC Receptacle (if
equipped)

CAUTION

Electrical Shock can cause injury.
Do not touch wires while

generator is running.

Never operate generator in rain or snow.
Never touch generator with wet hands or

electrical shock may occur.

NOTE: This section refers to charging 12V

batteries in other equipment like motor
vehicles or off-road vehicles. No
jump-starting is possible.

NOTE: Follow safety procedures when

handling batteries to avoid damage to
electrical components and battery
explosions. Refer to battery
manufacturers safety data sheet on
safety risks of working with batteries.
Refer to battery manufacturer's
instruction on battery charging/
maintaining procedures.

NOTE: Generator DC rated voltage is 12V. DC

circuit protector (E) will turn off
automatically if current above rated
fl ows during battery charging. Start
generator fi rst, then connect generator
to battery for charging. Before starting
to charge battery, ensure DC circuit
protector (E) is in RESET position. If
DC circuit protector (E) turns off again,
stop charging battery immediately and
contact a Kohler portable dealer.

NOTE: Do not connect a VRLA (valve

regulated lead acid) battery. To charge
a VRLA battery, a special (constant­voltage) battery charger is required.

NOTE: Do not connect any load to battery or

use engine starter motor while
charging. This causes high current to
fl ow through generator which will burn
out coil.

NOTE: Prior to charging battery, remove

positive and negative cables to battery.

1. Start generator.

2. Press DC circuit protector (E) in.

3. Connect red battery charger lead to positive
battery terminal. Connect black battery
charger lead to negative battery terminal. Do
not reverse these positions. Connect cord to
DC receptacle (F).

Operating Range of DC Power Supply
(Charging 12V battery only):

This power source is designed to charge
batteries up to 40Ah that are half-discharged.
Do not charge batteries of a higher capacity
than 40Ah.

12V Battery:

Time required for recharging a battery varies
depending on discharge level of battery. When
specifi c gravity of battery reaches 1.26 to 1.28,
charging is complete. When charging, check
battery’s specifi c gravity once an hour. Average
time for charging a half-discharged 40Ah
battery is approximately 5 hours. Be sure to
check battery fl uid level before charging.

DC Circuit Protector

NOTE: Reduce load of connected electric

device below specifi ed rated output of
generator if DC circuit protector (E)
turns off. If DC circuit protector (E)
turns off again, stop using device
immediately and contact a Kohler
portable dealer.

DC circuit protector (E) button will pop out,
stopping power to DC receptacle (F) when
electric device being connected to generator is
operating at current above rated fl ows. To use
this equipment again, press DC circuit protector
(E) button.

Starter Battery (if equipped)

As starter battery (O) is maintenance-free, just
check condition and tightness of connections
and its general cleanliness.

Circuit Breaker

Generating set's electrical circuit is protected
by one or more magnetothermal, differential or
thermal cut-out switches. If an overload and/or
short circuit occurs, supply of electrical energy
may be cut.

If necessary, replace circuit breaker (A)
in generating set with circuit breakers with
identical nominal ratings and specifi cations.

12 37 590 01 Rev. FKohlerPower.com

Clean Generating Set

1. Remove all dust and debris from around
exhaust.

2. Clean generating set, particularly alternator
and engine air inlets and outlets, using a
cloth and brush.

3. Check general condition of generating set
and replace any faulty parts.

Transporting Generator

Before transporting generator, check that bolts
are correctly tightened, close fuel valve (X)
and disconnect starter battery (O). Generator
should be transported in its normal operating
position; never lay it on its side. Ensure where
generator is to be stored or used is carefully
prepared beforehand.

Repairs/Service Parts

We recommend that you use a Kohler portable
dealer for all maintenance, service, and
replacement parts for engine. To fi nd a Kohler
portable dealer visit KohlerPower.com or call
1-800-544-2444 (U.S. and Canada).

Storage

Long-term storage of your generator will require
some preventative procedures to guard against
deterioration.

NOTE: Do not connect with any electrical

devices (unloaded operation).

If engine will be out of service for 2 months or
more follow procedure below.

1. Add Kohler PRO Series fuel treatment or
equivalent to fuel tank. Run engine 2-3
minutes to get stabilized fuel into fuel system
(failures due to untreated fuel are not
warrantable).

2. Change oil while engine is still warm from
operation. Remove spark plug (Q) and pour
about 1 oz. of engine oil into cylinder(s).
Replace spark plug (Q) and crank engine
slowly to distribute oil.

3. Clean generator.

4. Store generator in a dry, well-ventilated
place, with cover placed over it. When
covering generator, be sure to do so only
after engine and muffl er/shield have
completely cooled down. Generator must
remain in same position as normal operation.

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Troubleshooting

Do not attempt to service or replace major engine components, or any items that require special
timing or adjustment procedures. This work should be performed by a Kohler portable dealer.

Problem

Possible Cause

Engine Not

Starting/
Running

Abnormally

Engine

Stopped

No Electric

Current

Tripping of

Circuit

Breaker

Load connected to generating set
during start-up

●

Start and Stop control ON or OFF ●

Oil level too low ●●

Unsuitable fuel ●

Fuel level too low ●●

Fuel valve closed ●

Clogged fuel fi lter ●

Clogged fuel strainer ●

Clogged air fi lter ●

Faulty spark plug ●

Fuel supply blocked or leaking ●

Faulty starter battery ●

Blocked ventilation inlets ●

Circuit protectors not actuated ●

Faulty appliance supply cord ●

Faulty electrical sockets ●

Faulty alternator ●

Device connected or faulty cord ●

Overload ●

Battery Incorrectly Connected ●

14 37 590 01 Rev. FKohlerPower.com

Specifi cations

Model

PRO 3.7/

PRO 3.7 E

PRO 5.2/

PRO 5.2 E

PRO 7.5/

PRO 7.5 E

Overall Dimensions (L x W x H)

24.3 in. (617 mm)

18.8 in. (478 mm)

19.2 in. (488 mm)

26.4 in. (670 mm)

21.5 in. (545 mm)

21.1 in. (535 mm)

Dry Weight

138 lbs. (63 kg)/
154 lbs. (70 kg)

180 lbs. (82 kg)/

201 lbs. (91 kg)

199 lbs. (90 kg)/

220 lbs. (100 kg)

AC Rated Power

3000

Watt

(120 Volts x

25.0 Amps)
4500

Watt

(120 Volts x

37.5 Amps)

6300

Watt

(120 Volts x

52.5 Amps)

(240 Volts x

12.5 Amps)

(240 Volts x

18.8 Amps)

(240 Volts x

26.3 Amps)

AC Maximum Power

3700

Watt

(120 Volts x

30.8 Amps)

5200

Watt

(120 Volts x

43.3 Amps)

7500

Watt

(120 Volts x

62.5 Amps)

(240 Volts x

15.4 Amps)

(240 Volts x

21.7 Amps)

(240 Volts x

31.3 Amps)

DC Rated Power 100 Watt (12 Volts x 8.3 Amps)

Engine Specifi cations

Bore 2.8 in. (70 mm) 3.5 in. (89 mm)

Stroke 2.1 in. (54 mm) 2.7 in. (69 mm)

Displacement 12.7 cu. in. (208 cc) 26.2 cu. in. (429 cc)

Oil Capacity (Refi ll)

0.63 U.S. qt.
(0.60 L)

1.16 U.S. qt. (1.1 L)

Maximum Angle of Operation
(@ full oil level)*

25°

Run Time 9 hours (1/2 load) 13 hours (1/2 load) 12 hours (1/2 load)

Fuel See fuel section

Fuel Tank Capacity 3.4 gal. (13.0 L) 8 gal. (30.2 L)

Spark Plug Gap 0.03 in. (0.76 mm)

*Exceeding maximum angle of operation may cause engine damage from insuffi cient lubrication.
Additional specifi cation information can be found at KohlerPower.com.
Exhaust Emission Control System for models PRO 3.7, PRO 3.7 E, PRO 5.2, PRO 5.2 E, PRO 7.5

and PRO 7.5 E is EM for U.S. EPA, California, and Europe.

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Install Wheel Kit

Wheel Kit

Wheel Kit (Wheels and Legs)

Wheel Kit (4 Wheels)

NOTE: Tilt unit so fuel tank cap is upward to

ensure no fuel leakage.

NOTE: A clamping device or an assistant to

hold assembly while installing kit will
make process easier.

Wheel kit includes 2 wheels and mounting
hardware to be installed opposite of engine
side. Wheel kit and leg kit are designed to
be installed together. 2 wheel kits can be
combined for a 4 wheel confi guration.

1. Place 4 screws into holes of frame.

2. Bring bracket of wheel under frame and align
screws with bracket holes.

3. Thread nuts to screws. Torque to 221 in. lb.
(25 N·m).

Install Leg Kit

Leg Kit

NOTE: Tilt unit so fuel tank cap is upward to

ensure no fuel leakage.

NOTE: A clamping device or an assistant to

hold assembly while installing kit will
make process easier.

Leg kit includes 2 legs and mounting hardware.
Leg kit and wheel kit are designed to be
installed together. 2 leg kits can be combined
for a 4 legged confi guration.

1. Place 4 screws into holes of frame.

2. Bring leg under frame and align screws with
leg holes.

3. Thread nuts to screws. Torque to 221 in. lb.
(25 N·m).

Accessory System

Accessory kits available for models in table below which includes custom kits consisting of legs,
handles, wheels, lifting kits — whatever you want, any way you want it.

Accessory System

PRO 3.7/

3.7 E

PRO 5.2/

5.2 E

PRO 7.5 /

7.5 E GEN 5.0 WP 2.0 WP 3.0 TP 3.0

Wheel Kit ●●●●●●●

Leg Kit ●●●●●●●

Lifting Kit ●●●●

Wheelbarrow Handle Kit ●●●●●●●

Cord Management Kit ●●●●●●●

Hand Truck Handle Kit ●●●●

Isolator Kit ●●●●●●●