Remove Crankshaft; Remove Inner Breather Assembly; Remove Flywheel And Pto End Oil Seals; Honing - Kohler Courage SV710 Service Manual

Disassembly/Inspection and Service

Remove Crankshaft

Carefully pull crankshaft from crankcase.
Inspection and Service
Inspect gear teeth of crankshaft. If teeth are badly worn,
chipped, or some are missing, replacement of crankshaft
will be necessary.
Inspect crankshaft bearing surfaces for scoring,
grooving, etc. Measure running clearance between
crankshaft journals and their respective bearing bores.
Use an inside micrometer or telescoping gauge to
measure inside diameter of both bearing bores in vertical
and horizontal planes. Use an outside micrometer to
measure outside diameter of crankshaft main bearing
journals. Subtract journal diameters from their respective
bore diameters to get running clearances. Check results
against values in Specifi cations. If running clearances
are within specifi cation, and there is no evidence of
scoring, grooving, etc., no further reconditioning is
necessary. If bearing surfaces are worn or damaged,
crankcase and/or oil pan will need to be replaced.
Inspect crankshaft keyways. If worn or chipped,
replacement of crankshaft will be necessary.
Inspect crankpin for score marks or metallic pickup.
Slight score marks can be cleaned with crocus cloth
soaked in oil. If wear limits are exceeded, as stated in
Specifi cations, it will be necessary to replace crankshaft.

Remove Inner Breather Assembly

Breather system is designed to control amount of oil
in head area and still maintain necessary vacuum in
crankcase.
When pistons move downward, crankcase gases are
pushed past reed through mesh fi lter into intake system.
Upward travel of pistons closes reed and creates a
low vacuum in lower crankcase. Any oil separated out
through fi lter drains back into crankcase.
1. Remove screw securing inner breather cover and
gasket to crankcase.
2. Carefully remove cover, gasket, and breather fi lter.
Make sure drain back hole is not plugged or
restricted.

Remove Flywheel and PTO End Oil Seals

Remove oil seals from crankcase and oil pan.
Crankcase
Inspection and Service
Check all gasket surfaces to make sure they are free of
gasket fragments. Gasket surfaces must also be free of
deep scratches or nicks.
Check cylinder bore for scoring. In severe cases,
unburned fuel can cause scuffi ng and scoring of cylinder
wall. It washes necessary lubricating oils off piston and
cylinder wall. As raw fuel seeps down cylinder wall,
piston rings make metal to metal contact with wall.
Scoring of cylinder wall can also be caused by localized
hot spots resulting from blocked cooling fi ns or from
inadequate or contaminated lubrication.
66
If cylinder bore is badly scored, excessively worn,
tapered, or out-of-round, resizing is necessary. Use an
inside micrometer to determine amount of wear (refer
to Specifi cations). A 0.25 mm (0.010 in.) oversize piston
is available if resizing is selected. Initially, resize using
a boring bar, then use these following procedures for
honing cylinder.

Honing

Details
A
NOTE: Kohler pistons are custom-machined to exacting
tolerances. When over-sizing a cylinder, it
should be machined exactly 0.25 mm (0.010 in.)
over new diameter (refer to Specifi cations).
Oversize Kohler replacement piston will then fi t
correctly.
While most commercially available cylinder hones can
be used with either portable drills or drill presses, use
of a low speed drill press is preferred as it facilitates
more accurate alignment of bore in relation to crankshaft
crossbore. Honing is best accomplished at a drill speed
of about 250 RPM and 60 strokes per minute. After
installing coarse stones in hone, proceed as follows:
1. Lower hone into bore and after centering, adjust so
stones are in contact with cylinder wall. Use of a
commercial cutting-cooling agent is recommended.
2. With lower edge of each stone positioned even with
lowest edge of bore, start drill and honing process.
Move hone up and down while resizing to prevent
formation of cutting ridges. Check size frequently.
3. When bore is within 0.064 mm (0.0025 in.) of
desired size, remove coarse stones and replace
them with burnishing stones. Continue with
burnishing stones until bore is within 0.013 mm
(0.0005 in.) of desired size and then use fi nish
stones (220-280 grit) and polish bore to its fi nal size.
A crosshatch should be observed if honing is done
correctly. Crosshatch should intersect at
approximately 23°-33° off horizontal. Too fl at an
angle could cause rings to skip and wear
excessively, and too steep an angle will result in high
oil consumption.
KohlerEngines.com
A
23°-33° Crosshatch
32 690 01 Rev. G