Kohler Aegis 20 HP User manual

KOHLER® AEGIS 20,23 HP
LIQUID-COOLED
VERTICAL CRANKSHAFT
OWNER'S MANUAL

2
California
Proposition 65 Warning
Safety Precautions
Engine exhaust from this product
contains chemicals known to the
State of California to cause
cancer, birth defects, or other
reproductive harm.
WARNING
Explosive Fuel can cause fires and
severe burns.
Stop engine before filling fuel tank.
WARNING
Explosive Fuel!
Gasoline is extremely flammable
and its vapors can explode if
ignited. Store gasoline only in
approved containers, in well
ventilated, unoccupied buildings,
away from sparks or flames. Do not
fill the fuel tank while the engine is
hot or running, since spilled fuel
could ignite if it comes in contact
with hot parts or sparks from
ignition. Do not start the engine near
spilled fuel. ever use gasoline as a
cleaning agent.
Hot Parts!
Engine components can get
extremely hot from operation. To
prevent severe burns, do not touch
these areas while the engine is
running, or immediately after it is
turned off. ever operate the engine
with heat shields or guards
removed.
For Your Safety!
These precautions should be followed at all times. Failure to follow these precautions could result
in injury to yourself and others.
To insure safe operations please read the following statements and understand their meaning.
Also refer to your equipment owner's manual for other important safety information. This manual
contains safety precautions which are explained below. Please read carefully.
WARNING
Warning is used to indicate the presence of a hazard that can cause severe personal in ury, death,
or substantial property damage if the warning is ignored.
CAUTI N
Caution is used to indicate the presence of a hazard that will or can cause minor personal in ury
or property damage if the caution is ignored.
N TE
Note is used to notify people of installation, operation, or maintenance information that is important
but not hazard-related.
Hot Parts can cause severe burns.
Do not touch engine while operating
or just after stopping.
Hot Liquid!
The liquid coolant can get extremely
hot from operation. Turning the
radiator cap when the engine is hot
can allow steam and scalding liquid
to blow out and burn you severely.
Shut off machine. Only remove
radiator cap when cool enough to
touch with bare hands. Slowly
loosen cap to first stop to relieve
pressure before removing
completely.
Hot liquid can cause severe burns.
Do not loosen radiator cap while
engine is operating or warm to the
touch.
WARNING

3
Carbon Monoxide can cause
severe nausea, fainting or death.
Do not operate engine in closed or
confined area.
WARNING WARNING
Explosive Gas can cause fires and
severe acid burns.
Charge battery only in a well
ventilated area. Keep sources of
ignition away.
Accidental Starts!
Disabling engine. Accidental
starting can cause severe injury
or death. Before working on the
engine or equipment, disable the
engine as follows: 1) Disconnect the
spark plug lead(s). 2) Disconnect
negative (-) battery cable from
battery.
Lethal Exhaust Gases!
Engine exhaust gases contain
poisonous carbon monoxide.
Carbon monoxide is odorless,
colorless, and can cause death if
inhaled. Avoid inhaling exhaust
fumes, and never run the engine in
a closed building or confined area.
Explosive Gas!
Batteries produce explosive
hydrogen gas while being charged.
To prevent a fire or explosion,
charge batteries only in well
ventilated areas. Keep sparks, open
flames, and other sources of ignition
away from the battery at all times.
Keep batteries out of the reach of
children. Remove all jewelry when
servicing batteries.
Before disconnecting the negative
(-) ground cable, make sure all
switches are OFF. If O , a spark will
occur at the ground cable terminal
which could cause an explosion if
hydrogen gas or gasoline vapors
are present.
Safety Precautions (Cont.)
Accidental tarts can cause severe
injury or death.
Disconnect and ground spark plug
leads before servicing.
WARNING
Electrical Shock!
ever touch electrical wires or
components while the engine is
running. They can be sources of
electrical shock.
CAUTION
Electrical hock can cause injury.
Do not touch wires while engine is
running.
Rotating Parts can cause severe
injury.
Stay away while engine is in
operation.
WARNING
Rotating Parts!
Keep hands, feet, hair, and clothing
away from all moving parts to
prevent injury. ever operate the
engine with covers, shrouds, or
guards removed.
Congratulations  You have selected a fine four-cycle, twin cylinder, liquid-cooled engine. Kohler designs long
life strength and on-the- ob durability into each engine...making a Kohler engine dependable...dependability you
can count on. Here are some reasons why:
 Efficient overhead valve design, and pressure lubrication provide maximum power, torque, and reliability
under all operating conditions.
 Dependable, maintenance free electronic ignition ensures fast, easy starts time after time.
 Kohler engines are easy to service. All routine service areas (like the dipstick and oil fill, air cleaner, spark
plugs, and carburetor) are easily and quickly accessible.
 Parts sub ect to the most wear and tear (like the cylinder liner and camshaft) are made from precision
formulated cast iron.
 Every Kohler engine is backed by a worldwide network of over 10,000 distributors and dealers. Service
support is ust a phone call away. Call 1-800-544-2444 (U.S. & Canada) for Sales & Service assistance.
To keep your engine in top operating condition, follow the maintenance procedures in this manual.

4
il Fill/
Dipstick
Electric
Starter
Engine
Identification Label
Spark Plug
Valve Cover with
Integral Breather
il Filter
Fuel
Pump
Spark
Plug
Upper Blower Housing and
Air Intake Screen Assembly
Retaining
Strap
Figure 1. Typical Kohler® Aegis Vertical Shaft Engine.
Figure 3. il Container Logo.
Refer to Maintenance Instructions beginning on
page 8 for detailed oil check, oil change, and oil
filter change procedures.
Fuel Recommendations
WARNING: Explosive Fuel!
Gasoline is extremely flammable and its vapors can
explode if ignited. Store gasoline only in approved
containers, in well ventilated, unoccupied buildings,
away from sparks or flames. Do not fill the fuel tank
while the engine is hot or running, since spilled fuel
could ignite if it comes in contact with hot parts or
sparks from ignition. Do not start the engine near
spilled fuel. ever use gasoline as a cleaning agent.
General Recommendations
Purchase gasoline in small quantities and store in
clean, approved containers. A container with a capacity
of 2 gallons or less with a pouring spout is
recommended. Such a container is easier to handle
and helps eliminate spillage during refueling.
Do not use gasoline left over from the previous season,
to minimize gum deposits in your fuel system and to
insure easy starting.
Do not add oil to the gasoline. Do not overfill the fuel
tank. Leave room for the fuel to expand.
Oil Recommendations
Using the proper type and weight of oil in the
crankcase is extremely important. So is checking oil
daily and changing oil regularly. Failure to use the
correct oil, or using dirty oil, causes premature engine
wear and failure.
il Type
Use high quality detergent oil of API (American
Petroleum Institute) service class SG, SH, SJ or
higher. Synthetic oils may be used. Select the viscosity
based on the air temperature at the time of operation as
shown in the following table.
Figure 2. Viscosity Grades Table.
NOTE: Using other than service class SG, SH, SJ or
higher oil or extending oil change intervals
longer than recommended can cause engine
damage.
A logo or symbol on oil containers identifies the API
service class and SAE viscosity grade. See Figure 3.
*Use of synthetic oil having 5W-20 or 5W-30 rating is acceptable,
up to 4°C (40°).
**Synthetic oils will provide better starting in extreme cold
below -23°C (-10°).
*
**

5
Fuel Type
For best results use only clean, fresh, unleaded
gasoline with the pump sticker octane rating of 87 or
higher. In countries using the Research method, it
should be 90 octane minimum.
Unleaded gasoline is recommended as it leaves less
combustion chamber deposits. Leaded gasoline may
be used in areas where unleaded is not available and
exhaust emissions are not regulated. Be aware
however, that the cylinder heads may require more
frequent service.
Gasoline/Alcohol blends
Gasohol (up to 10% ethyl alcohol, 90% unleaded
gasoline by volume) is approved as a fuel for Kohler
engines. Other gasoline/alcohol blends are not
approved.
Gasoline/Ether blends
Methyl Tertiary Butyl Ether (MTBE) and unleaded
gasoline blends (up to a maximum of 15% MTBE by
volume) are approved as a fuel for Kohler engines.
Other gasoline/ether blends are not approved.
Coolant Recommendations
Use equal parts of ethylene glycol (anti-freeze) and
water only. Distilled or deionized water is
recommended, especially in areas where the water
contains a high mineral content. Propylene glycol
based anti-freeze is not recommended.
This mixture will provide protection from -37° C (-34° F)
to 108° C (226° F). For protection and use outside the
indicated temperature limits, follow the anti-freeze
manufacturers instructions on the container, but do not
exceed 70% anti-freeze.
DO NOT use anti-freeze with stop-leak additive(s), or
put any other additives in the cooling system.
Engine dentification Numbers
When ordering parts, or in any communication
involving an engine, always give the Model,
Specification, and Serial Numbers of the engine.
The engine identification numbers appear on a decal
affixed to the engine blower housing. Include letter
suffixes, if there are any.
Record your engine identification numbers on the
identification label (Figure 4) for future reference.
Figure 4. Engine Identification Label.
The Emission Compliance Period referred to on the
Emission Control or Air Index label indicates the
number of operating hours for which the engine has
been shown to meet Federal and CARB emission
requirements. The following table provides the Engine
Compliance Period (in hours) associated with the
category descriptor found on the certification label.
Emission Compliance Period (Hours)
EPA
CARB
Category C
250 Hours
Moderate
125 Hours
Category B
500 Hours
Intermediate
250 Hours
Category A
1000 Hours
Extended
500 Hours
Refer to certification label for engine displacement.
Exhaust Emission Control System for models LV625
and LV675 is EM.
Model Designation
Model LV675 for example: L designates liquid cooled,
V designates vertical crankshaft, and 675 designates
engine size or the approximate displacement in cubic
centimeters. A letter suffix designates a specific
version as follows:
Suffix Designates
S Electric Start
*Small ff-Road Engines
IMPORTANT ENGINE IN ORMATION
THIS ENGINE MEETS U.S. EPA 2004 AND
CALI ORNIA 2006 AND LATER EMISSION
CONTROL REGULATIONS OR SI SORE*
FAMILY
DISPL. (CC)
M DEL N .
SPEC. N .
SERIAL N .
EMISSION COMPLIANCE PERIOD:
EPA: CARB:
KOHLER CO. KOHLER, WISCONSIN USA
THIS ENGINE IS CERTI IED TO OPERATE
ON:
RE ER TO OWNER'S MANUAL OR SA ETY,
MAINTENANCE SPECS AND ADJUSTMENTS.
OR SALES/SERVICE IN US/CANADA, CALL:
1-800-544-2444
www.kohlerengines.com

6
Pre-Start Checklist
 Check oil level. Add oil if low. Do not overfill.
 Check coolant level. Add coolant if low.
 Check fuel level. Add fuel if low.
 Check radiator, cooling air intake areas and
external surfaces of engine. Make sure they are
clean and unobstructed.
 Check that the air cleaner components and all
shrouds, equipment covers, and guards are in
place and securely fastened.
 Check that any clutches or transmissions are
disengaged or placed in neutral. This is especially
important on equipment with hydrostatic drive. The
shift lever must be exactly in neutral to prevent
resistance which could keep the engine from
starting.
WARNING: Lethal Exhaust Gases!
Engine exhaust gases contain poisonous carbon
monoxide. Carbon monoxide is odorless, colorless,
and can cause death if inhaled. Avoid inhaling exhaust
fumes, and never run the engine in a closed building or
confined area.
Cold Weather Starting Hints
1. The cooling system must be filled with coolant
capable of providing proper protection against
freezing at the lowest temperature expected (see
Coolant Recommendations on page 5).
2. Be sure to use the proper oil for the temperature
expected. See Figure 2 on page 4.
3. Declutch all possible external loads.
4. A warm battery has much more starting capacity
than a cold battery.
5. Use fresh winter grade fuel. NOTE: Winter grade
gasoline has higher volatility to improve starting.
Do not use gasoline left over from summer.
Starting
1. Place the throttle control midway between the
slow and fast positions. Place the choke
control into the on position.
2. Start the engine by activating the key switch.
Release the switch as soon as the engine starts.
NOTE: Do not crank the engine continuously for
more than 10 seconds at a time. If the
engine does not start, allow a 60 second
cool down period between starting
attempts. Failure to follow these
guidelines can burn out the starter motor.
NOTE: Upon start-up, a metallic ticking may
occur. This is caused by hydraulic lifter
leakdown during storage. Run the engine
for 5 minutes. The noise will normally
cease in the first minute. If noise
continues, run the engine at mid-throttle
for 20 minutes. If noise persists, take the
engine to your local Kohler Service outlet.
If the starter does not turn the engine over, shut
off starter immediately. Do not make further
attempts to start the engine until the condition is
corrected. Do not ump start using another battery
(refer to Battery on page 7). See your Kohler
Engine Service Dealer for trouble analysis.
3. For a Cold Engine  Gradually return the choke
control to the off position after the engine starts
and warms up.
The engine/equipment may be operated during
the warm up period, but it may be necessary to
leave the choke partially on until the engine warms
up.
4. For a Warm Engine  Return choke to off
position as soon as engine starts.
Stopping
1. Remove the load by disengaging all PTO
attachments.
2. Position the throttle control somewhere between
half and full throttle; then stop the engine.
Operating Instructions
Also read the operating instructions of the equipment this engine powers.

7
Battery
A 12 volt battery is normally used. Refer to the
operating instructions of the equipment this engine
powers for specific battery requirements.
If the battery charge is not sufficient to crank the
engine, recharge the battery (see page 15).
Operating
Angle of peration
This engine will operate continuously at angles up to
20°. Check oil level to assure crankcase oil level is at
the FULL mark on the dipstick.
Refer to the operating instructions of the equipment
this engine powers. Because of equipment design or
application, there may be more stringent restrictions
regarding the angle of operation.
NOTE: Do not operate this engine continuously at
angles exceeding 20° in any direction. Engine
damage could result from insufficient
lubrication.
Cooling
NOTE: If debris builds up on the air intake screen,
radiator, or other cooling areas, stop the
engine immediately and clean. Operating the
engine with blocked or dirty air intake and
cooling areas can cause extensive damage
due to overheating. See Clean Air Intake/
Cooling Area, page 14.
High Temperature Sensor
Some engines are equipped with a high temperature
sensor mounted in the cooling system. If the safe
operating temperature is exceeded, it will either shut
off the engine or activate a warning signal, depending
on the application.
If the warning light illuminates or engine kills indicating
excessive operating temperatures:
1. Make sure all air intake and cooling surfaces are
clean and free of debris.
2. After engine has sufficiently cooled, check the
coolant level in system to make sure it is not low.
See Checking Coolant Level, page 10.
3. Check the system for external leaks.
4. If the cause is none of the above or cannot be
identified, contact an Authorized Kohler Engine
Dealer for appropriate diagnosis and correction.
WARNING: Hot Parts!
Engine components can get extremely hot from
operation. To prevent severe burns, do not touch these
areas while the engine is running, or immediately after
it is turned off. ever operate the engine with heat
shields or guards removed.
Engine Speed
NOTE: Do not tamper with the governor setting to
increase the maximum engine speed.
Overspeed is hazardous and will void the
engine warranty. The maximum allowable high
idle speed for these engines is 3750 RPM.

8
Maintenance Instructions
Maintenance, repair, or replacement of the emission control devices and systems, which are being done at
the customers expense, may be performed by any non-road engine repair establishment or individual.
Warranty repairs must be performed by an authorized Kohler service outlet.
WARNING: Accidental Starts!
Disabling engine. Accidental starting can cause severe injury or death. Before working on the engine or
equipment, disable the engine as follows: 1) Disconnect the spark plug lead(s). 2) Disconnect negative (-) battery
cable from battery.
Maintenance Schedule
These required maintenance procedures should be performed at the frequency stated in the table. They should
also be included as part of any seasonal tune-up.
Maintenance RequiredFrequency
 Fill fuel tank.
 Check oil level.
 Check coolant level.
 Check air cleaner for dirty1, loose, or damaged parts.
 Check air intake screen, radiator, and cooling areas, clean as necessary1.
 Service precleaner element1.
 Replace air cleaner element1.
 Clean and check cooling areas1.
 Replace fuel filter.
Every 25 Hours
Daily or Before
Starting Engine
Every 100 Hours
Annually or
Every 200 Hours
 Change oil and oil filter (more frequently under severe conditions).
 Check spark plug condition and gap.
 Have solenoid shift starter disassembled and cleaned2.
 Replace spark plugs.
Annually or
Every 500 Hours
1Perform these maintenance procedures more frequently under extremely dusty, dirty conditions.
2Have a Kohler Engine Service Dealer perform these services.
Every 2 Years or
Every 1000 Hours
Check Oil Level
The importance of checking and maintaining the proper
oil level in the crankcase cannot be overemphasized.
Check oil BEF RE EACH USE as follows:
1. Make sure the engine is stopped, level, and is
cool so the oil has had time to drain into the sump.
2. To keep dirt, debris, etc., out of the engine, clean
the area around the dipstick before removing it.
3. Unthread and remove the dipstick; wipe oil off.
Reinsert the dipstick into the tube and rest the oil
fill cap on the tube. Do not thread the cap onto the
tube. See Figure 5. Figure 5. Checking il Level.
4. Pull the dipstick out and check the oil level.
The oil level should be up to, but not over, the
FULL mark on the dipstick. See Figure 6.
 Change engine coolant.

9
Figure 6. il Level Dipstick.
5. If the level is low, add oil of the proper type, up to
the FULL mark on the dipstick. (Refer to Oil
Type on page 4.) Always check the level with the
dipstick before adding more oil.
NOTE: To prevent extensive engine wear or
damage, always maintain the proper oil
level in the crankcase. Never operate the
engine with the oil level below the ADD
mark or over the FULL mark on the
dipstick.
il Sentry
Some engines are equipped with an optional Oil
Sentry oil pressure switch. If the oil pressure
decreases below an acceptable level, the Oil Sentry
will either shut off the engine or activate a warning
signal, depending on the application.
NOTE: Make sure the oil level is checked BEF RE
EACH USE and is maintained up to the
FULL mark on the dipstick. This includes
engines equipped with Oil Sentry.
Change Oil and Filter
Change the oil and oil filter every 200 hours or
annually, whichever comes first (more often under
severe conditions). Refill with service class SG, SH, SJ
or higher oil, as specified in the Viscosity Grades
table (Figure 2) on page 4. Always use a genuine
Kohler oil filter, Part No. 52 050 02-S.
Change the oil while the engine is still warm. The oil
will flow more freely and carry away more impurities.
Make sure the engine is level when filling, checking, or
changing the oil.
Change the oil and oil filter as follows (see Figure 7):
1. To keep dirt, debris, etc., out of the engine, clean
the area around the oil fill cap/dipstick before
removing it.
2. Remove one of the oil drain plugs and the oil fill
cap/dipstick. Be sure to allow ample time for
complete drainage.
3. Before removing the oil filter, clean the area
around the oil filter to keep dirt and debris out of
the engine. Remove the old filter and wipe off the
filter adapter with a clean cloth.
4. Reinstall the drain plug. Make sure it is tightened
to 13.6 N·m (10 ft. lb.) torque.
5. Place a new replacement filter in a shallow pan
with the open end up. Pour new oil, of the proper
type, in through the threaded center hole. Stop
pouring when the oil reaches the bottom of the
threads. Allow a minute or two for the oil to be
absorbed by the filter material.
6. Put a drop of oil on your fingertip and wipe it on
the rubber gasket of the new oil filter.
7. Install the new oil filter to the filter adapter. Hand
tighten the filter clockwise until the rubber gasket
contacts the adapter, then tighten the filter an
additional 2/3 to 1 turn.
8. Fill the crankcase with new oil of the proper type,
to the FULL mark on the dipstick. Refer to Oil
Type and Check Oil Level on pages 4 and 8.
Always check the level with the dipstick before
adding more oil.
9. Reinstall the oil fill cap/dipstick and tighten
securely by turning to the right.
perating
Range
"Full" Mark
Figure 7. il Drain Plugs and il Filter.
il Drain Plug
il
Filter il Drain Plug

10
Cooling System Maintenance and Service
Important service notes:
 Do not operate the engine without coolant in
system.
 Do not remove the radiator cap when hot. Engine
coolant is hot and under pressure and can cause
severe burns.
 To prevent engine overheating and damage, use
the recommended anti-freeze mixture in the
cooling system.
 To prevent engine damage, do not pour cold water
into a hot engine.
 To prevent engine damage, do not use anti-freeze
with stop-leak additive(s) or put other additives in
the cooling systems.
 Cooling system capacity is approximately 1.4 L
(1.47 qt.).
Maintenance
This engine is liquid-cooled, circulating a mixture of
ethylene glycol and water for dependable operation. A
pump is used to circulate the coolant through the
system and radiator. A thermostat contained in the
system assures automatic temperature control and
rapid warm-up. Correct coolant level and cleaning any
debris accumulation from the inlet screen and radiator
surfaces are critical to insuring long life, proper system
performance, and preventing overheating. Check the
coolant level in the overflow reservoir, and clean away
any debris accumulation daily or before each use. At
the same time, inspect the hoses and all connections
for signs of leakage.
Servicing
Engine coolant should be changed every 2 years or
every 1000 hours, whichever comes first. When
changing the engine coolant, the system should also
be flushed to remove any contaminants left behind
during draining. Following are recommended
procedures for checking, draining, flushing, and filling
the cooling system.
Checking Coolant Level
The coolant level should be checked at the overflow
reservoir, located under the upper blower housing
assembly.
1. Unhook the retaining straps and remove the upper
blower housing and screen assembly. See Figures
8 and 9.
Figure 8. Unhooking Retaining Straps.
Figure 9. Removing Upper Blower Housing and
Screen Assembly.
2. Check the coolant level within the overflow
reservoir. Coolant level should be between the
Max. Level and Min. Level marks on the
reservoir. See Figure 10. Do not operate the
engine with the coolant level below the Min.
Level mark.
Add coolant to the overflow reservoir as required.
Use equal parts of ethylene glycol and water only
(distilled or deionized water is recommended).
Figure 10. Coolant Levels on Reservoir.