Kohler KS540 [71/92] Disassembly inspection and service
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Kohler KS540 [71/92] Disassembly inspection and service

Kohler KS540 [71/92] Disassembly inspection and service
71
Disassembly/Inspection and Service
22 690 01 Rev. -- KohlerEngines.com
Remove Connecting Rod and Piston
C
A
B
D
A
Connecting Rod
Screw
B Rod Cap
C Piston Assembly D Connecting Rod
NOTE: If a carbon ridge is present at top of bore, use a
ridge reamer to remove it before attempting to
remove piston.
1. Rotate crankshaft so rod journal is in 8 o’clock
position.
2. Remove screws and connecting rod cap.
3. Carefully push connecting rod and piston away from
crankshaft and out of cylinder bore.
Inspection and Service
Check bearing area (big end) for score marks and
excessive wear. Service replacement connecting rods
are available in STD crankpin size.
Remove Piston from Connecting Rod
B
A
D
A
C
A Piston Pin Retainer B Piston Pin
C Piston Assembly D Connecting Rod
Remove piston pin retainers and piston pin. Separate
piston from connecting rod.
Piston and Rings Inspection
Scuffi ng and scoring of pistons and cylinder walls occurs
when internal temperatures approach welding point
of piston. Temperatures high enough to do this are
created by friction, which is usually attributed to improper
lubrication, and/or overheating of engine.
Normally, very little wear takes place in piston boss-
piston pin area. If original piston and connecting rod
can be reused after new rings are installed, original pin
can also be reused, but new piston pin retainers are
required. Piston pin is part of piston assembly; if pin boss
or pin are worn or damaged, a new piston assembly is
required.
Ring failure is usually indicated by excessive oil
consumption and blue exhaust smoke. When rings fail,
oil is allowed to enter combustion chamber where it is
burned along with fuel. High oil consumption can also
occur when piston ring end gap is incorrect because
ring cannot properly conform to cylinder wall under this
condition. Oil control is also lost when ring gaps are not
staggered during installation.
When cylinder temperatures get too high, lacquer and
varnish collect on pistons causing rings to stick which
results in rapid wear. A worn ring usually takes on a
shiny or bright appearance.
Scratches on rings and pistons are caused by abrasive
material such as carbon, dirt, or pieces of hard metal.
Detonation damage occurs when a portion of fuel charge
ignites spontaneously from heat and pressure shortly
after ignition. This creates two fl ame fronts that meet and
explode to create extreme hammering pressures on a
specifi c area of piston. Detonation generally occurs from
using low octane fuels.
Preignition or ignition of fuel charge before timed spark
can cause damage similar to detonation. Preignition
damage is often more severe than detonation damage.
Preignition is caused by a hot spot in combustion
chamber from sources such as glowing carbon deposits,
blocked fi ns, improperly seated valve, or wrong spark
plug.
Replacement pistons are available in STD bore size.
Replacement pistons include new piston ring sets and
new piston pins.
Replacement ring sets are also available separately
for STD pistons. Always use new piston rings when
installing pistons. Never reuse old rings.
Remove Piston Rings
1. Remove top and center compression rings using a
ring expander.
2. Remove oil control ring rails, then remove spacer.

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