Remove Camshaft; Automatic Compression Release (Acr); Remove Balance Shafts - Kohler KS530 Service Manual

Disassembly/Inspection and Service

Remove Camshaft

A Camshaft
Carefully pull upward on camshaft to remove assembly
from crankcase cavity.

Automatic Compression Release (ACR)

These engines are equipped with an ACR mechanism.
ACR lowers compression at cranking speeds to make
starting easier.
Operation
ACR mechanism consists of an actuating spring and
a pivoting fl yweight/control pin assembly. At cranking
speeds (700 RPM or lower), spring holds fl yweight in
and rounded surface of control pin protrudes above
exhaust cam lobe. This pushes exhaust valve off its seat
during fi rst part of compression stroke. Compression
is reduced to an eff ective ratio of about 2:1 during
cranking.
After starting, when engine speed exceeds 700 RPM,
centrifugal force overcomes force of fl yweight spring.
Flyweight moves outward, rotating control pin to expose
fl at surface, which is lower than cam lobe. Control pin
no longer has any eff ect on exhaust valve, and engine
operates at full power.
When engine is stopped, spring returns fl yweight/control
pin assembly to compression release position, ready for
next start.
Benefi ts
As a result of reduced compression at cranking speeds,
several important benefi ts are obtained:
1. Electric start models can use a smaller starter and
battery which are more practical for application.
2. 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.
3. Choke control setting is less critical with ACR. If
fl ooding occurs, excess fuel is blown out opened
exhaust valve and does not hamper starting.
70
A
B
B Crankcase
KohlerEngines.com
4. Engines with ACR start much faster in cold weather
than engines without ACR.
5. Engines with ACR can be started with spark plugs
which are worn or fouled. Engines without ACR are
more diffi cult to start with those same spark plugs.
Cam Gear Inspection and Service
Inspect gear teeth and cam lobes of camshaft. If lobes
exhibit excessive wear, or teeth are worn, chipped or
broken, replacement of camshaft will be necessary.

Remove Balance Shafts

A Balance Shaft 1
1. Rotate crankshaft clockwise to line up lower timing
marks on crankshaft gear and balance shaft 1 gear.
2. Lift balance shaft 1 from crankcase and mark BS1
for reassembly.
3. Rotate crankshaft clockwise to move crankshaft
weights, then lift balance shaft 2 from crankcase and
mark BS2 for reassembly.
B
A
B Balance Shaft 2
22 690 01 Rev. --