Section 10. Inspection And Reconditioning - Kohler CH11-16 Service Manual

Inspection and Reconditioning
This section covers the operation, inspection, and
repair/reconditioning of major internal engine
components. The following components are not
covered in this section. They are covered in sections of
their own:
Air Cleaner, Section 4
Carburetor & External Governor, Section 5
Ignition, Charging & Electric Starter, Section 8
Clean all parts thoroughly. Only clean parts can be
accurately inspected and gauged for wear or damage.
There are many commercially available cleaners that
will quickly remove grease, oil, and grime from
engine parts. When such a cleaner is used, follow the
manufacturer's instructions and safety precautions
carefully. Make sure all traces of the cleaner are
removed before the engine is reassembled and placed
into operation. Even small amounts of these cleaners
can quickly break down the lubricating properties of
engine oil.
Use an aerosol gasket remover, paint stripper, or
lacquer thinner to remove any old sealant. Apply the
solvent, allow time for it to work, and then brush the
surface with a brass wire brush. After the old sealant
is removed, clean the surface with isopropyl alcohol,
lacquer thinner, or aerosol electrical contact cleaner.
Do not scrape the surfaces, as any scratches, nicks, or
burrs can result in leaks. See Service Bulletin 252 for
further information.
Refer to A Guide to Engine Rebuilding (TP-2150-A)
for additional information. Measurement Guide
(TP-2159-B) and Engine Inspection Data Record
(TP-2435) are also available; use these to record
inspection results.
Automatic Compression Release (ACR)
This engine is equipped with an Automatic
Compression Release (ACR) mechanism. ACR lowers
compression at cranking speeds to make starting
easier.
Section 10
Operation
The ACR mechanism consists of a lever and control
pin assembly attached to the gear on the camshaft. At
cranking speeds (700 RPM or lower), the control pin
protrudes above the exhaust cam lobe. This pushes the
exhaust valve off its seat during the first part of the
compression stroke. The reduced compression results
in an effective compression ratio during cranking of
about 2:1.
After starting, engine speed increases to over 700
RPM. Centrifugal force moves the lever and the
control pin drops into the recess in the exhaust cam
lobe. When in the recess, the control pin has no effect
on the exhaust valve and the engine operates at full
power.
When the engine is stopped, the spring returns the
lever and control pin assembly to the compression
release position ready for the next start.
Camshaft
Inspection and Service
Inspect the gear teeth of the camshaft. If the teeth are
badly worn, chipped, or some are missing,
replacement of the camshaft and crankshaft will be
necessary.
Crankshaft
Inspection and Service
Inspect the gear teeth of the crankshaft. If the teeth are
badly worn, chipped, or some are missing,
replacement of the crankshaft will be necessary.
Inspect the crankshaft bearings for scoring, grooving,
etc. Do not replace bearings unless they shown signs
of damage or are out of running clearance
specifications. If the crankshaft turns easily and
noiselessly, and there is no evidence of scoring,
grooving, etc., on the races or bearing surfaces, the
bearings can be reused.
Section 10
Internal Components
10
10.1