Kohler 18-26 User manual

1
C OMMAND 18-26 HP
O WNER ' S M ANUAL
H ORIZONTAL C RANKSHAFT

2
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. Never use
gasoline as a cleaning agent.
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. Never operate the
engine with covers, shrouds, or
guards removed.
Hot Parts can cause severe burns.
Do not touch engine while operating
or just after stopping.
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. Never operate the
engine with heat shields or guards
removed.
Electrical Shock can cause injury.
Do not touch wires while engine is
running.
CAUTION
Electrical Shock!
Never touch electrical wires or
components while the engine is
running. They can be sources of
electrical shock.
California
Proposition 65 Warning
Engine exhaust from this product
contains chemicals known to the
State of California to cause
cancer, birth defects, or other
reproductive harm.
Safety Precautions
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 injury,
death, or substantial property damage if the warning is ignored.
CAUTION
Caution is used to indicate the presence of a hazard that will or can cause minor personal injury
or property damage if the warning is ignored.
NOTE
Note is used to notify people of installation, operation, or maintenance information that is
important but not hazard-related.
For Your Safety!
These precautions should be followed at all times. Failure to follow these precautions could result
in injury to yourself and others.

3
Safety Precautions (Cont.)
Accidental Starts can cause
severe injury or death.
Disconnect and ground spark plug
leads before servicing.
WARNING
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. Beforeworkingontheengine
or equipment, disable the engine as
follows: 1) Disconnect the spark
pluglead(s).2)Disconnectnegative
(-) battery cable from battery.
Explosive Gas!
Batteriesproduceexplosive
hydrogengaswhilebeingcharged.
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
jewelrywhen servicingbatteries.
Beforedisconnectingthe negative
(–) ground cable, make sure all
switches are OFF. If ON, a spark
will occur at the ground cable
terminal which could cause an
explosionifhydrogen gas or
gasolinevaporsare present.
Congratulations – You have selected a fine four-cycle, twin cylinder, air-cooled engine. Kohler designs long life
strength and on-the-job durability into each engine...making a Kohler engine dependable...dependability you can
count on. Here are some reasons why:
• Efficient overhead valve design and full 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, oil fill, air cleaner, and spark
plugs are easily and quickly accessible.
• Parts subject to the most wear and tear (like the cylinder liner* and camshaft) are made from precision
formulated cast iron. Because the cylinder liner* can be rebored, these engines can last even longer.
*CH25/26 engines have POWER-BORE™ Cylinders. These cylinders are plated with nickel-silicon to give
increased power, virtually permanent cylinder life, superior oil control, and reduced exhaust emissions. These
cylinderscannotberebored.
• Every Kohler engine is backed by a worldwide network of over 10,000 distributors and dealers. Service
support is just 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.
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.

4
Figure 1. Typical Command Horizontal Shaft Engine (CH18-25).
Figure 2. CH26 Command Horizontal Shaft Engine.
Air Cleaner
OilFill
Rectifier-Regulator
Throttle Body Intake Manifold
IgnitionCoil
Fuel Injectors
IgnitionCoil
Oil Filter
Oil Cooler
Oil Filter
Rectifier-Regulator
Fuel
Pump
Electric
Starter
Oil Cooler
Dipstick
Side Oil Drain Plugs

5
Fuel Recommendations
WARNING: Explosive Fuel!
Gasoline is extremely flammable and its vapors can
explodeifignited.Store gasoline only in approved
containers,inwell 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. Never
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 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.
Fuel Type
For best results use only clean, fresh, unleaded
gasoline with a 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
combustionchamberdeposits and reduces harmful
exhaust emissions. Leaded gasoline is not
recommendedand must not be used onCH26 engines.
Gasoline/Alcohol blends
Gasohol (up to 10% ethyl alcohol, 90% unleaded
gasolineby volume) isapproved as afuel for Kohler
engines.Other gasoline/alcoholblendsare notapproved.
Gasoline/Ether blends
Methyl Tertiary Butyl Ether (MTBE) and unleaded
gasoline blends (up to a maximum of 15% MTBE by
volume)are approved asa fuelforKohler engines. Other
gasoline/etherblends arenot approved.
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.
Oil Type
Use high quality detergent oil of API (American
Petroleum Institute) service class SG, SH, SJ or
higher. Select the viscosity based on the air
temperature at the time of operation as shown in the
followingtable.
*
*Use of synthetic oil having 5W-20 or 5W-30 rating is
acceptable, up to 40°F.
**Synthetic oils will provide better starting in extreme
cold(below -10°F).
Figure 3. Viscosity Grades Table.
NOTE: Using other than service class SG, SH, SJ or
higheroilor extending oilchange intervals
longerthan recommendedcancause engine
damage.
A logo or symbol on oil containers identifies the API
service class and SAE viscosity grade. See Figure 4.
**
Figure 4. Oil Container Logo.
Refer to “Maintenance Instructions” beginning on
page 8 for detailed oil check, oil change, and oil
filter change procedures.

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Engine Identification Numbers
Whenordering parts, orin any communicationinvolving
an engine, always give the Model, Specification, and
Serial Numbers of the engine.
Theengine identification numbersappear on adecal (or
decals) affixed to the engine shrouding. Include letter
suffixes, if there are any.
Recordyour engine identificationnumberson the
identificationlabel below(Figure5) forfuture reference.
Figure 5. Engine Identification Labels.
KOHLER CO. KOHLER, WI USA
KOHLER CO. KOHLER, WI USA
If your engine has this identification label, it is
certified to meet EPA/CARB standards.
*Small Off-Road Engines
MODEL NO.
SPEC. NO.
DISPL (CC)
SERIAL NO.
REFERTOOWNER'SMANUALFOR
SAFETY,MAINTENANCESPECSAND
ADJUSTMENTS.FORSALESAND
SERVICEINUS/CANADACALL:
1-800-544-2444
IMPORTANT ENGINE INFORMATION
THISENGINEMEETSU.S. EPA
PHASE 1 AND 1995-1999
CALIFORNIA EMISSION CONTROL
REGULATIONSFORSORE*
FAMILY
MODEL NO.
SPEC. NO.
DISPL (CC)
SERIAL NO.
REFERTOOWNER'SMANUALFOR
SAFETY,MAINTENANCESPECSAND
ADJUSTMENTS.FORSALESAND
SERVICEINUS/CANADACALL:
1-800-544-2444
Operating Instructions
Also read the operating instructions of the equipment
thisenginepowers.
Pre-Start Checklist
• Check oil level. Add oil if low. Do not overfill.
• Check fuel level. Add fuel if low.
• Check 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. Be sure to use the proper oil for the temperature
expected. See Figure 3 on page 5.
2. Disengage all possible external loads.
3. Set speed control at part throttle position.
4. Be sure the battery is in good condition. A warm
battery has much more starting capacity than a
cold battery.
5. Use fresh winter grade fuel. NOTE: Winter grade
gasoline has a higher volatility to improve starting.
Do not use gasoline left over from summer.
Starting
CH18-26Engines:
1. Place the throttle control midway between the
‘‘slow’’ and ‘‘fast’’ positions. Place the choke
control (CH18-25 engines only) into the ‘‘on’’
position. See Figure 6.

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4. For a Warm Engine – Return choke to “off”
position as soon as engine starts.
Stopping
1. Removethe loadby disengagingall PTOdriven
attachments.
2. For CH18-25 Engines Without A Shutdown
Solenoid: Move the throttle to the “slow” or
“low” idle position. Allow the engine to run at idle
for 30-60 seconds; then stop the engine.
For CH18-25 Engines Equipped With A
Shutdown Solenoid: Position the throttle control
somewhere between half and full throttle; then stop
theengine.
For CH26 Engines: Turn key ‘‘off’’ to stop
engine.
Battery
A 12 volt battery is normally used. Refer to the
operating instructions of the equipment this engine
powersforspecific batteryrequirements.
If the battery charge is not sufficient to crank the
engine, recharge the battery (see page 12).
Operating
Angle of Operation
This engine will operate continuously at angles up to
25°. Check oil level to assure crankcase oil level is at
the “F” mark on the dipstick.
Refer to the operating instructions of the equipment this
enginepowers.Because of equipmentdesign or
application, there may be more stringent restrictions
regardingthe angleof operation.
NOTE: Do not operate this engine continuously at
angles exceeding 25° in any direction. Engine
damagecould result frominsufficient
lubrication.
Cooling
NOTE: If debris builds up on the grass screen or other
cooling air intake 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.
Figure 6. Optional Engine Mounted Throttle and
ChokeControls (CH18-25).
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
cooldown periodbetweenstarting
attempts. Failure to follow these
guidelines can burn out, or permanently
damage, the starter motor.
NOTE: Upon start up, a metallic ticking may
occur. This is caused by the 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 authorized Kohler
Engine Service Dealer.
If the engine develops sufficient speed to
disengage the starter but does not keep running (a
false start), the engine rotation must be allowed to
come to a complete stop before atttempting to
restart the engine. If the starter is engaged while
the flywheel is rotating, the starter pinion and
flywheel ring gear may clash resulting in damage to
the starter.
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 jump start using another battery (refer to
“Battery” on this page). See your Kohler Engine
Service Dealer for service assistance.
CH18-25Engines Only:
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.
Choke
Control Throttle
Control

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• Replacefuel filter1(CH26engines).
Daily or Before
Starting Engine
Maintenance RequiredFrequency • Fill fuel tank.
• Checkoillevel.
• Check air cleaner for dirty1, loose, or damaged parts.
• Check air intake and cooling areas, clean as necessary1.
• Serviceprecleanerelement1.
Every 25 Hours • Replaceair cleanerelement1.
• Changeoil. (Morefrequentlyunder severeconditions.)
• Removecooling shroudsandclean coolingareas1,3.
• Check oil cooler fins, clean as necessary (if equipped).
• Check spark plug condition and gap.
• Change oil filter.
Annually or
Every 500 Hours • Havebendix starterdrive serviced2.
• Have solenoid shift starter disassembled and cleaned2.
Every 100 Hours
Every 200 Hours
Every 1500 Hours
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.
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. Never operate the engine with heat shields
orguards removed.
1
Performthesemaintenance procedures morefrequentlyunder extremely dusty, dirty conditions.
2
Have a Kohler Engine Service Dealer perform this service.
3
Cleanout Kits 25 755 20 (black) or 25 755 21 (gold) allow cooling areas to be cleaned without removing shrouds.
Engine Speed
NOTE: Do not tamper with the governor setting to
increase the maximum engine speed.
Overspeedis hazardousandwill voidthe
enginewarranty. Themaximum allowablehigh
idle speed for these engines is 3750 RPM, no
load.
Check Oil Level
Theimportance of checkingand maintaining theproper
oil level in the crankcase cannot be overemphasized.
Checkoil BEFORE 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. Remove the dipstick; wipe oil off. Reinsert the
dipstick into the tube and press all the way down.
4. Remove the dipstick and check the oil level.
The oil level should be up to, but not over, the “F”
mark on the dipstick. See Figure 7.

9
Figure 7. Oil Level Dipstick.
5. If the level is low, add oil of the proper type, up to
the “F” mark on the dipstick. (Refer to “Oil Type” on
page 5.) Always check the level with the dipstick
beforeadding moreoil.
NOTE: To preventextensive enginewear or
damage, always maintain the proper oil
levelin the crankcase.Never operate the
engine with the oil level below the “L” mark
or over the “F” mark on the dipstick.
Oil Sentry™
Some engines are equipped with an optional Oil
Sentry™ oil pressure switch monitor. 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 BEFORE
EACH USE and is maintained up to the “F”
mark on the dipstick. This includes engines
equipped with Oil Sentry™.
Change Oil and Filter, Service Oil Cooler
Change Oil
Changeoil afterevery 100 hours ofoperation (more
frequentlyunder severeconditions).Refill withservice
class SG, SH, SJ or higher oil as specified in the
‘‘Viscosity Grades’’ table (Figure 3) on page 5.
Change the oil while the engine is still warm. The oil will
flow freely and carry away more impurities. Make sure
the engine is level when filling, checking, and changing
the oil.
Change the oil as follows (see Figures 8 and 9):
1. To keep dirt, debris, etc., out of the engine, clean
the area around the oil fill cap/dipstick before
removingit.
2. Remove one of the oil drain plugs, oil fill cap, and
dipstick. Be sure to allow ample time for complete
drainage.
3. Reinstall the drain plug. Make sure it is tightened
to 13.6 N·m (10 ft. lb.) torque.
4. Fill the crankcase, with new oil of the proper type,
to the “F” mark on the dipstick. Refer to “Oil Type”
on page 5. Always check the level with the dipstick
beforeadding moreoil.
5. Reinstall the oil fill cap and tighten securely.
Reinstall dipstick.
NOTE: To preventextensive enginewear or
damage, always maintain the proper oil
levelin the crankcase.Never operate the
engine with the oil level below the “L” mark
or over the “F” mark on the dipstick.
“F” Mark
Operating
Range
Figure 8. Oil Drain Plugs, Oil Filter, and Oil Cooler
(CH25shown).
Figure 9. Oil Drain Plugs, Oil Filter, and Oil Cooler
(CH26shown).
Oil Filter
Oil Drain Plug Oil Cooler
Oil Filter
Oil Cooler Oil Drain Plug

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Change Oil Filter
Replace the oil filter at least every other oil change
(every 200 hours of operation). Always use a genuine
Kohler oil filter, Part No. 12 050 01.
Replace the oil filter as follows:
1. Drain the oil from the engine crankcase.
2. Allow the oil filter to drain.
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. Wipe off the
surface where the oil filter mounts.
4. 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.
5. Put a drop of oil on your fingertip and wipe it on the
rubbergasket.
6. Install the replacement oil filter to the filter adapter
or oil cooler. Turn the oil filter clockwise until the
rubber gasket contacts the filter adapter or oil
cooler, then tighten the filter an additional
1/2 turn.
7. Reinstall the drain plug. Make sure it is tightened
to 13.6 N·m (10 ft. lb.) torque.
8. Fill the crankcase with new oil of the proper type to
the “F” mark on the dipstick. Add 0.24 L (1/2 pint)
of oil for the filter capacity.
9. Start the engine and check for oil leaks. Correct
any leaks before placing the engine into service.
Check oil level to be sure it is up to but not over the
“F” mark.
Service Oil Cooler
Some engines are equipped with an oil cooler. Inspect
and clean the oil cooler every 100 hours of operation
(morefrequently undersevereconditions). Oilcooler
must be kept free of debris.
To service the oil cooler, clean off the outside fins with a
brush or with compressed air.
Service Precleaner and Air Cleaner Element
This engine is equipped with a replaceable, high density
paper air cleaner element. Some engines are also
equippedwith an oiled,foam precleanerwhich
surrounds the paper element. See Figure 10.
Figure 10. Air Cleaner System Components.
Check the air cleaner daily or before starting the
engine. Check for a buildup of dirt and debris around
the air cleaner system. Keep this area clean. Also
check for loose or damaged components. Replace all
bentordamaged air cleaner components.
NOTE: Operatingtheengine withlooseor damaged
air cleaner components could allow unfiltered
air into the engine causing premature wear
and failure.
Service Precleaner
If so equipped, wash and reoil the precleaner every 25
hours of operation (more often under extremely dusty
or dirty conditions).
1. Loosenthe coverretaining knoband removethe
cover.
2. Remove the precleaner from the paper element.
3. Wash the precleaner in warm water with detergent.
Rinse the precleaner thoroughly until all traces of
detergent are eliminated. Squeeze out excess
water (do not wring). Allow the precleaner to air
dry.
4. Saturate the precleaner with new engine oil.
Squeeze out all excess oil.
5. Reinstallthe precleanerover thepaperelement.
6. Reinstallthe aircleanercover.Securecover with
thecover retaining knob.
Precleaner
Element Cover
Element
Air Cleaner
Cover
Cover Knob
Element
Cover Nut

11
47 083 03 65 mm deep x 178 mm O.D.
24 083 03 74 mm deep x 178 mm O.D.
7. When precleaner replacement is necessary, order
genuineKohler parts.
24 083 02 61 mm deep x 173 mm O.D.
24 083 05 71 mm deep x 173 mm O.D.
Clean Air Intake/Cooling Areas
To ensure proper cooling, make sure the grass screen,
cooling fins, and other external surfaces of the engine
are kept clean at all times.
Every 100 hours ofoperation(more oftenunder
extremely dusty, dirty conditions), remove the blower
housing and other cooling shrouds.* Clean the cooling
fins and external surfaces as necessary. Make sure the
coolingshroudsare reinstalled.
NOTE: Operating the engine with a blocked grass
screen, dirty or plugged cooling fins, and/or
coolingshrouds removed, willcause engine
damagedue tooverheating.
*Cleanout kits 25 755 20 (black) or 25 755 21 (gold)
allow inspection and cleanout of the cooling fins.
Ignition System
CH18-25 Engines - Useanelectronic Capacitive
Discharge (CD) ignition system. Other than
periodically checking/replacing the spark plugs, no
maintenance, timing, or adjustments are necessary or
possiblewiththissystem.
CH26 Engines - Incorporate acomputercontrolled and
monitored ignition system with individual coils. Other
than periodically checking/replacing the spark plugs, no
maintenance, timing, or adjustments are necessary or
possible with this system.
Check Spark Plugs
Every 200 hours of operation, remove the spark plugs,
check condition, and reset the gap or replace with new
plugs as necessary. The standard spark plug is a
Champion®RC12YC (Kohler Part No. 12 132 02). A
high-performancespark plug,Champion®Premium
Gold 2071 (used on Pro Series engines, Kohler Part
No.12132 06) isalsoavailable. Equivalent alternate
brand plugs can also be used.
1. Beforeremoving thesparkplug, clean thearea
around the base of the plug to keep dirt and debris
out of the engine.
2. Remove the plug and check its condition. Replace
the plug if worn or reuse is questionable.
NOTE: Do not clean the spark plug in a machine
using abrasive grit. Some grit could
remain in the spark plug and enter the
enginecausing extensivewearand
damage.
Service Paper Element
Every 100 hours ofoperation(more oftenunder
extremely dusty or dirty conditions) replace the paper
element.
1. Loosenthe coverretaining knoband removethe
cover.
2. Removetheelementcover nut,element cover,and
paperelement withprecleaner.
3. Removetheprecleaner(if soequipped) fromthe
paperelement.
4. Do not wash the paper element or use
pressurized air, as this will damage the element.
Replace a dirty, bent, or damaged element with a
genuineKohler element.Handlenew elements
carefully; do not use if the sealing surfaces are
bentor damaged.
5. When servicing the air cleaner, check the air
cleaner base. Make sure it is secured and not bent
or damaged. Also check the element cover for
damageor improper fit.Replaceall damagedair
cleanercomponents.
NOTE: If any loose dirt or debris fell on the air
cleaner base when the element was
removed,carefully removeitand wipethe
base clean. Be careful that none of it
drops into the intake throat. Check the
condition of the rubber seal on the air
cleaner stud. If the condition is
questionable in any way, replace it with
the new seal packaged with the
replacementelement.
6. Reinstallthe paperelement, precleaner, element
cover, elementcover nut,andair cleanercover.
Securecover with thecover retaining knob.
7. When element replacement is necessary, order
genuineKohler parts.

12
Figure 11. Servicing Spark Plug.
4. Reinstall the spark plug into the cylinder head.
Torque the spark plug to 24.4/29.8 N·m
(18/22 ft. lb.).
Battery Charging
WARNING: Explosive Gas!
Batteriesproduceexplosive hydrogengaswhile 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.
Removeall jewelry whenservicingbatteries.
Before disconnecting the negative (–) ground cable,
make sure all switches are OFF. If ON, a spark will
occur at the ground cable terminal which could cause
anexplosionifhydrogen gas or gasoline vaporsare
present.
NOTE: Do not apply 12 volt DC to kill terminal of
ignitionmodule.
Ground
Electrode
Spark Plug
Wire Gauge
Fuel System
WARNING: Fuel System Under Pressure!
The CH26 fuel system operates under high pressure,
and the fuel filter and fuel line used must be approved
system components only. Use of substitute parts can
result in system failure, gasoline leakage and possible
explosion.
Fuel Filter
CH18-25 Engines: Some engines are equipped with
an in-line fuel filter. Periodically inspect the filter and
replace when dirty. Always use genuine Kohler parts.
CH26 Engines: A special,highvolume, high pressure
filter with greater filtration capabilities and internal
surface area is used. See Figure 12.
3. Check the gap using a wire feeler gauge. Adjust
the gap to 0.76 mm (0.030 in.) by carefully
bendingthe ground electrode.SeeFigure 11.
Figure 12. CH26 Fuel Filter and Line.
Replacement is recommended every 1500 hours, or
more frequently under extremely dusty or dirty
conditions. When replacement is necessary, always
use genuine Kohler parts.
Fuel Line
CH26 Engines: A special fuel line capable of
withstanding the high pressure of the EFI fuel system is
used (must meet SAE R9 specifications). See Figure
12. If fuel line must be replaced, see your Kohler Engine
ServiceDealer.
Fuel Filter
Fuel Line
0.76 mm
(0.030 in.) Gap

13
• Make sure the air cleaner element is clean and all
aircleaner element componentsare fastened
securely.
If, after checking the items listed above, the engine is
hard to start, runs roughly, or stalls at low idle speed, it
may be necessary to adjust or service the carburetor.
Adjust Carburetor
NOTE: Certifiedenginesmay have a fixed idleor
limiter cap on the idle fuel adjusting needle. Do
not attempt steps 1 and 2 below. Proceed
directly to step 3. Step 4 can only be
performed within the limits allowed by the cap.
1. With the engine stopped, turn the low idle fuel
adjusting needle in (clockwise) until it bottoms
lightly.
NOTE: The tip of the low idle fuel adjusting
needle is tapered to critical dimensions.
Damage to the needle and the seat in
carburetor body will result if the needle is
forced.
2. Preliminary Low Idle Fuel Needle Setting: Turn
the adjusting needle out (counterclockwise) from
lightly bottomed position 1-5/8 turns.
3. Start the engine and run at half throttle for 5 to 10
minutes to warm up. The engine must be warm
before making final settings (steps 4 and 5).
4. Low Idle Fuel Needle Setting: Place the throttle
into the “idle” or “slow” position. Turn the low
idle fuel adjusting needle in (slowly) from the
preliminary setting until engine speed decreases
and then back out approximately 3/4 to 1 turn to
obtainthe bestlow-speedperformance.
5. Low Idle Speed Setting: Place the throttle
control into the “idle” or “slow” position. Set the
low idle speed to 1200 RPM* (± 75 RPM) by
turning the low idle speed adjusting screw in or
out. Check the speed using a tachometer.
*NOTE: The actual low idle speed depends on the
application – refer to equipment
manufacturer’s recommendations. The
recommendedlowidlespeed for basic
engines is 1200 RPM. To ensure best
results when setting the low idle fuel
needle, the low idle speed must not
exceed 1200 RPM (± 75 RPM).
CH18-25 Carburetor Troubleshooting and
Adjustments
NOTE: Carburetoradjustmentsshould be made only
after the engine has warmed up.
The carburetor is designed to deliver the correct
fuel-to-airmixture to theengineunder alloperating
conditions. The high idle is set at the factory and cannot
be adjusted. The low idle fuel adjusting needle is also
set at the factory and normally does not need
adjustment.
If the engine is hard to start, runs roughly, or stalls at
low idle speed, it may be necessary to adjust or service
thecarburetor.
Figure 13. Carburetor (CH18-25).
Troubleshooting
If engine troubles are experienced that appear to be
fuel system related, check the following areas before
adjustingthe carburetor.
• Make sure the fuel tank is filled with clean, fresh
gasoline.
• Make sure the fuel tank cap vent is not blocked
and that it is operating properly.
• If the fuel tank is equipped with a shut-off valve,
make sure it is open.
• If the engine is equipped with an in-line fuel filter,
make sure it is clean and unobstructed. Replace
the filter if necessary.
• Make sure fuel is reaching the carburetor. This
includes checking the fuel lines and fuel pump for
restrictions or faulty components, replace as
necessary.
Low Idle
Speed Adj.
Screw
Low Idle
Fuel Adj.
Needle &
Spring
Fixed Main Jet
(under optional
solenoid)

14
CH26 Electronic Fuel Injection (EFI)
System
The EFI system is a complete, electronically controlled
fuel management system, designed to deliver a
preciselycontrolled fuel flowunder all operating
conditions. The electronic control unit (ECU), the
‘‘brain’’ of the system, automatically adjusts fuel
delivery and ignition timing based upon load, speed,
operatingtemperature, and exhaustemission levels.
The low idle speed is the only manual adjustment
possible.
The ECU continuously monitors operation of the EFI
system. If it detects a problem or fault within the
system, it will illuminate the malfunction indicator light
(MIL), which is mounted in view of the operator. This is a
signalthat normal, programmedoperation has been
affected,and service byanauthorized KohlerEngine
Dealeris required.
Troubleshooting
If the MIL comes on, or the engine becomes hard to
start, runs roughly, or stalls at low idle speed, initial
checks should be made in the following areas:
• Make sure the fuel tank is filled with clean, fresh
gasoline, and shut-off valve (if so equipped) is
openedcompletely.
• Make sure fuel tank vent cap is not blocked and it
isoperating properly.
• Make sure the air cleaner element and precleaner
are clean and all components are properly
secured. Clean or replace as necessary.
• Make sure the proper fuel filter is being used, and
it is clean and unobstructed. Replace filter only
with genuine Kohler parts.
• Make sure all connections to sensors, ECU, and
fuel injectors are properly secured.
• Make sure a good 12 volt battery is being used and
is fully charged.
If these checks do not correct the problem, or the MIL
remains on, further diagnosis and servicing by an
authorized Kohler Engine Dealer is necessary.
Adjustment – EFI Throttle Body
Low Idle Speed (RPM) is the only adjustment that can
be made. All other fuel calibrations are permanently
preset and controlled by the ECU. The standard low idle
speed is 1500 RPM* (+ 75 RPM).
*NOTE: The actual low idle speed depends on the
application-- refertoequipmentmanufacturer's
recommendations.
When an EFI engine is started cold, the ECU will briefly
set a higher (200-400 RPM) low idle speed, similar to a
fast idle. Do not attempt to perform any readjustment
duringthis ‘‘warm-up’’ period.
If adjustment is to be made, the engine must be at
operating temperature, air cleaner in place, and check
engine light must be off (no fault codes present).
1. Start the engine and run at half throttle for 5 to 10
minutes to warm up.
2. Place the throttle control into the ‘‘idle’’ or
‘‘slow’’ position.
3. Turn the low idle speed adjusting screw in or out
and check RPM with a tachometer. See Figure 14.
Figure 14.
Low Idle Speed
Adjusting Screw
Fuel Rail
Throttle Body
Intake Manifold

15
Parts Ordering
Theengine Specification, Model,and SerialNumbers
arerequired whenorderingreplacementpartsfrom your
KohlerEngine ServiceDealer.Thesenumbers arefound
on the identification plate which is affixed to the engine
shrouding. Include letter suffixes if there are any. See
“EngineIdentification Numbers”onpage 6.
Always insist on genuine Kohler parts. All genuine
Kohler parts meet strict standards for fit, reliability, and
performance.
Major Repair
Majorrepair information isavailable inKohlerEngine
ServiceManuals. However, majorrepair generally
requires the attention of a trained mechanic and the use
of special tools and equipment. Your Kohler Engine
Service Dealer has the facilities, training, and genuine
Kohler replacement parts necessary to perform this
service. For Sales & Service assistance call
1-800-544-2444(U.S. & Canada)or contactyour
KohlerEngine Dealer orService Distributor, they're in
theYellow PagesunderEngines-Gasoline.
Model Designation
ModelCH20S for example:C designates Command
engine, H designates horizontal crankshaft, and 20
designates horsepower. A letter suffix designates a
specificversionasfollows:
Suffix Designates
S Electric Start
GS GeneratorApplication/ElectricStart
ST Electric Start/Retractable Start
QS Quiet Model/Electric Start
EP Electric Plant
CS Clutch Model/Electric Start
Will Not Start ••• ••••
Hard Starting •• ••••
Possible Cause No Improper Dirt In Dirty Incorrect Engine DirtyAir Faulty
Problem Fuel Fuel Fuel Line/System Grass Screen Oil Level Overloaded Cleaner Spark Plug
Stops Suddenly • • ••••
Lacks Power •• •••••
Operates Erratically •• • • • •
Knocks or Pings ••••
Skips or Misfires •• • • •
Backfires ••••
Overheats • ••••
HighFuel Consumption •••
Troubleshooting
When troubles occur, be sure to check the simple causes which, at first, may seem too obvious to be considered.
For example, a starting problem could be caused by an empty fuel tank. Some common causes of engine troubles
are listed in the following table.
Do not attempt to service or replace major engine components, or any items that require special timing or
adjustmentprocedures. Have yourKohlerEngine ServiceDealerdo thiswork.
Storage
If the engine will be out of service for two months or
more,use the followingstorage procedure:
1. Clean the exterior surfaces of the engine.
2. Change the oil and filter while the engine is still
warmfrom operation. See“ChangeOil andOil
Filter” on page 9.
3. The fuel system must be completely emptied, or
the gasoline must be treated with a stabilizer to
prevent deterioration. If you choose to use a
stabilizer, followthe manufacturers
recommendations, and add the correct amount for
the capacity of the fuel system. Fill the fuel tank
with clean, fresh gasoline. Run the engine for 2-3
minutes to get stabilized fuel into the carburetor.
Closefuel shut-off valvewhen unitisbeing stored
ortransported.
To empty the system, run the engine until the tank
and system are empty.
4. Remove the spark plugs. Add one tablespoon of
engine oil into each spark plug hole. Install the
plugs, but do not connect the plug leads. Crank the
enginetwo orthreerevolutions.
5. Store the engine in a clean, dry place.

16
LIMITED 2 YEAR COMMAND ENGINE WARRANTY
We warrant to the original consumer that each new COMMAND engine sold by us will be free from manufacturing defects in materials or
workmanship in normal service for a period of two (2) years from date of purchase, provided it is operated and maintained in accordance with
Kohler Co.’s instructions and manuals.
Our obligation under this warranty is expressly limited, at our option, to the replacement or repair at Kohler Co., Kohler, Wisconsin 53044, or
at a service facility designated by us of such parts as inspection shall disclose to have been defective.
EXCLUSIONS:
This warranty does not apply to defects caused by casualty or unreasonable use, including faulty repairs by others and failure to provide
reasonable and necessary maintenance.
The following items are not covered by this warranty:
Engine accessories such as fuel tanks, clutches, transmissions, power-drive assemblies, and batteries, unless supplied or installed by Kohler
Co. These are subject to the warranties, if any, of their manufacturers.
WESHALLNOTBELIABLEFORSPECIAL,INDIRECT,INCIDENTAL,ORCONSEQUENTIAL DAMAGESOFANY KIND,includingbut not
limited to labor costs or transportation charges in connection with the repair or replacement of defective parts.
ANYIMPLIEDORSTATUARYWARRANTIES,INCLUDINGWARRANTYOFMERCHANTABILITYORFITNESSFORAPARTICULAR
PURPOSE,AREEXPRESSLY LIMITED TO THE DURATION OF THIS WRITTEN WARRANTY.We make no other expresswarranty,noris
any one authorized to make any in our behalf.
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 limitation or exclusion 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.
TOOBTAINWARRANTYSERVICE:
Purchaser must bring the engine to an authorized Kohler service facility. For the facility nearest you, consult your Yellow Pages or write
Kohler Co., Attn: Engine Warranty Service Dept., Kohler, Wisconsin, 53044.
ENGINEDIVISION,KOHLERCO.,KOHLER,WISCONSIN53044
Specifications
Model: ................................................ CH18 ..................CH20.................. CH22 ................. CH25/CH26
Bore: ............................... in. (mm)... 3.03 (77).............3.03 (77) ............ 3.03 (77)#................... 3.27 (83)/3.27 (83)
Stroke: ............................ in. (mm)... 2.64 (67).............2.64 (67) ............ 2.64 (67) ............ 2.64 (67)/2.64 (67)
Displacement:................ in3(cm3)... 38.1 (624)...........38.1 (624) .......... 38.1 (624)#............... 44.0 (725)/44.0 (725)
Power (@3600 RPM): .....HP (kW)... 18* (13.4) ...........20* (14.9) ........... 22* (16.4)........... 25* (18.4)/26 (19.4 )
Max. Torque: ........... (ft.lbs. @ RPM) ... 30 (41) @2500 .....32 (44) @2500 .... 33 (45) @2500 .... 39.5 (54) @2400/41.6 (56.4) @2200
Compression Ratio: ......................... 8.5:1....................8.5:1 ................... 8.5:1 ................... 9.0:1/9.0:1
Weight:............................. lbs. (kg) ... 90 (41) ................90 (41)................ 90 (41) ............... 94 (43)/94 (43)
Oil Capacity (w/filter): .. U.S. qt. (L)... 2.1 (2) .................2.1 (2) ................. 2.1 (2) ................ 2.1 (2)/2.1 (2)
Lubrication:................................................ Full Pressure w/full Flow Filter
*Horsepower ratings are established in accordance with Society of Automotive Engineers – Small Engine Test Code – J1349
GROSS. Kohler Co. reserves the right to change product specifications, design, and standard equipment without notice and
without incurring obligation.
#CH22 engines with Spec. Numbers of 765xx have bore size of 3.15 in. (80 mm) and displacement of 41.1 in3(674 cm3).

17
KOHLER CO.
FEDERAL AND CALIFORNIA EMISSION CONTROL SYSTEMS
LIMITED WARRANTY
UTILITY AND LAWN AND GARDEN ENGINES
The U.S. Environmental Protection Agency (EPA), the California Air Resources Board (CARB), and Kohler Co. are pleased to explain the Federal
and California Emission Control Systems Warranty on your utility/lawn/garden equipment engine (herein engine). For California, engines
produced in 1995 and later must be designed, built and equipped to meet the state’s stringent anti-smog standards. In other states, new 1997
and later model year engines must be designed, built and equipped, at the time of sale, to meet the U.S. EPA regulations for small non-road
engines. The engine must be free from defects in materials and workmanship which cause it to fail to conform with U.S. EPA standards for the
first two years of engine use from the date of sale to the ultimate purchaser. Kohler Co. must warrant the emission control system on the engine
for the period of time listed above, provided there has been no abuse, neglect or improper maintenance.
The emission control system may include parts such as the carburetor or fuel injection system, the ignition system, and catalytic converter.
Also included are the hoses, belts and connectors and other emission related assemblies.
Where a warrantable condition exists, Kohler Co. will repair the engine at no cost, including diagnosis (if the diagnostic work is performed at an
authorized dealer), parts and labor.
MANUFACTURER’SWARRANTYCOVERAGE
Engines produced in 1995 or later are warranted for two years in California. In other states, 1997 and later model year engines are warranted for
two years. If any emission related part on the engine is defective, the part will be repaired or replaced by Kohler Co. free of charge.
OWNER’SWARRANTYRESPONSIBILITIES
(a) The engine owner is responsible for the performance of the required maintenance listed in the owner’s manual. Kohler Co. recommends
that you retain all receipts covering maintenance on the engine, but Kohler Co. cannot deny warranty solely for the lack of receipts or for
your failure to assure that all scheduled maintenance was performed.
(b) Be aware, however, that Kohler Co. may deny warranty coverage if the engine or a part has failed due to abuse, neglect, improper
maintenance or unapproved modifications.
(c) For warranty repairs, the engine must be presented to a Kohler Co. service center as soon as a problem exists. Call 1-800-544-2444 for
the names of the nearest service centers. The warranty repairs should be completed in a reasonable amount of time, not to exceed 30
days.
If you have any questions regarding warranty rights and responsibilities, you should contact Kohler Co. Engine Service at 1-920-457-4441.
COVERAGE
Kohler Co. warrants to the ultimate purchaser and each subsequent purchaser that the engine will be designed, built and equipped, at the time
of sale, to meet all applicable regulations. Kohler Co. also warrants to the initial purchaser and each subsequent purchaser, that the engine is
free from defects in materials and workmanship which cause the engine to fail to conform with applicable regulations for a period of two years.
Engines produced in 1995 or later are warranted for two years in California. For 1997 and later model years, EPA requires manufacturers to
warrant engines for two years in all other states. These warranty periods will begin on the date the engine is purchased by the initial purchaser.
If any emission related part on the engine is defective, the part will be replaced by Kohler Co. at no cost to the owner. Kohler Co. is liable for
damages to other engine components caused by the failure of a warranted part still under warranty.
Kohler Co. shall remedy warranty defects at any authorized Kohler Co. engine dealer or warranty station. Warranty repair work done at an
authorized dealer or warranty station shall be free of charge to the owner if such work determines that a warranted part is defective.
Listed below are the parts covered by the Federal and California Emission Control Systems Warranty. Some parts listed below may require
scheduled maintenance and are warranted up to the first scheduled replacement point for that part. The warranted parts are:
•Carburetor assembly •Ignition module(s) with high tension lead
•Throttle body (EFI Systems) •Spark advance module (if equipped)
•Catalytic muffler (if equipped) •Oxygen, speed, throttle position, and temperature sensors (if equipped)
•Fuel metering valve (if equipped) •Electronic control unit (if equipped)
•Crankcase breather •Fuel injectors (EFI Systems)
•Fuel pressure regulator (EFI Systems) •Air filter, fuel filter, and spark plugs (only to first scheduled replacement point)
Continued on next page.

18
LIMITATIONS
This Emission Control Systems Warranty shall not cover any of the following:
(a) repair or replacement required because of misuse or neglect, improper maintenance, repairs improperly performed or replacements not
conforming to Kohler Co. specifications that adversely affect performance and/or durability and alterations or modifications not
recommended or approved in writing by Kohler Co.,
(b) replacement of parts and other services and adjustments necessary for required maintenance at and after the first scheduled replacement
point,
(c) consequential damages such as loss of time, inconvenience, loss of use of the engine or equipment, etc.,
(d) diagnosis and inspection fees that do not result in eligible warranty service being performed, and
(e) any add-on or modified part, or malfunction of authorized parts due to the use of add-on or modified parts.
MAINTENANCEANDREPAIRREQUIREMENTS
The owner is responsible for the proper use and maintenance of the engine. Kohler Co. recommends that all receipts and records covering the
performance of regular maintenance be retained in case questions arise. If the engine is resold during the warranty period, the maintenance
records should be transferred to each subsequent owner. Kohler Co. reserves the right to deny warranty coverage if the engine has not been
properly maintained; however, Kohler Co. may not deny warranty repairs solely because of the lack of repair maintenance or failure to keep
maintenance records.
Normal maintenance, replacement or repair of emission control devices and systems may be performed by any repair establishment or
individual; however, warranty repairs must be performed by a Kohler authorized service center. Any replacement part or service that
is equivalent in performance and durability may be used in non-warranty maintenance or repairs, and shall not reduce the warranty obligations of the
engine manufacturer.

19

ENGINE DIVISION, KOHLER CO., KOHLER, WISCONSIN 53044 LITHOIN U.S.A.
FORMNO.: TP-2474-E
ISSUED: 12/94
REVISED: 5/99
MAILED:
FORSALES ANDSERVICEINFORMATION
IN U.S. AND CANADA, CALL
1-800-544-2444