Kohler Command PRO CH440 Service Manual page 83

Remove Closure Plate
NOTE: Do not pry on gasket surface of crankcase or
closure plate, as this can cause damage and
leakage.
NOTE: Some engines have a closure plate gasket;
some engines use RTV to secure closure plate
to crankcase.
1. Remove screws securing closure plate to crankcase.
2. Remove closure plate, gasket (if equipped), and
dowel pins (if required) from crankcase. Note
position of dowel pins for reassembly. Discard old
gasket (if equipped).
3. Remove shims from crankshaft and camshaft.
Inspection
Inspect main bearing surface for wear or damage (refer
to Specifi cations). Replace closure plate if required.
Remove Balance Shaft (if equipped)
Remove balance shaft by pulling it straight out of
crankcase.
Remove Camshaft and Valve Tappets
1. Remove camshaft by pulling it straight out of
crankcase.
2. Remove valve tappets by pulling them straight out of
crankcase. Mark their positions.
Automatic Compression Release (ACR)
ACR Operation Details
B
A
E
A Camshaft
Decompression
C
Weight
E Arm
17 690 01 Rev. L
C
D
B Exhaust Cam Lobe
D Return Spring
KohlerEngines.com
Disassembly/Inspection and Service
ACR mechanism consists of a spring-loaded arm and
sliding pin mounted to camshaft. When engine is rotating
at low cranking speeds, arm holds pin so it protrudes
above heel of exhaust cam. This holds exhaust valve off
of its seat during fi rst part of compression stroke.
After engine speed increases centrifugal force causes
spring-loaded arm to move outward causing pin to
retract. When in this position pin has no eff ect on
exhaust valve and engine operates at full compression
and power.
Benefi ts
As a result of reduced compression at cranking speeds,
several important benefi ts are obtained:
1. Manual (retractable) starting is much easier. Without
ACR, manual starting would be virtually impossible.
2. Electric start models can use a smaller starter and
battery more practical for application.
3. ACR eliminates need for a spark retard/advance
mechanism. A spark retard/advance mechanism
would be required on engines without ACR to
prevent kickback which would occur during starting.
ACR eliminates this kickback making manual
starting safer.
4. Choke control setting is less critical with ACR. In
event of fl ooding, excess fuel is blown out opened
exhaust valve and does not hamper starting.
5. Engines with ACR start much faster in cold weather
than engines without ACR.
6. Engines with ACR can be started with worn or fouled
spark plugs. Engines without ACR are more diffi cult
to start with those same spark plugs.
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