Kohler K9J Service Manual page 22

9. Low compression.
Engine Uses Excessive Amount of Oil
1. Incorrect oil viscosity or type.
2. Clogged or improperly assembled breather
system.
3. Worn or broken piston rings.
4. Worn cylinder bore.
5. Worn valve stems and/or guides.
EXTERNAL ENGINE INSPECTION
0 Before cleaning or disassembling the engine,
check its external appearance and condition.
This inspection can give clues to what might
be found inside the engine (and the cause)
once it is disassembled.
0 Check for buildup of dirt and debris on the
crankcase, cooling fins, grass screen and
other external surfaces. Dirt or debris in these
areas are causes of overheating.
0 Check for obvious fuel and oil leaks and dam-
aged components. Excessive oil leakage can
indicate a clogged or improperly assembled
breather, worn or damaged seals and gaskets
or loose or improperly torqued fasteners.
0 Check the air cleaner cover, element cover
and air cleaner base for damage or indications
of improper fit or seal.
0 Check the air cleaner element. Look for holes,
tears, cracked or damaged sealing surfaces or
other damage that could allow dirt to enter the
engine. Also note if the element is clogged or
restricted. These conditions could indicate that
the air cleaner has been underserviced.
0 Check the carburetor throat for dirt. Dirt in the
throat is further indication that the air cleaner
is not functioning properly.
0 Check the oil level. Note if the oil level is
within the operating range on the dipstick, or if
it is low or overfilled.
0 Check the condition of the oil. Drain the oil
into a container - it should flow freely. Check
for metal chips and other foreign particles.
NOTE: It is good practice to drain oil at a location
away from the workbench. Be sure to allow ample
time for complete drainage.
Sludge is a natural by-product of combustion; a
small accumu_lation is normal. Excessive sludge
formation could indicate that the oil has not been
changed as recommended, an incorrect type or
weight of oil has been used, over-rich carburetor
settings or weak ignition, to name a few.
4.2
CLEANING THE ENGINE
After inspecting the external condition of the en-
gine, clean it thoroughly before disassembling.
Also clean individual components as the engine is
disassembled. Only clean parts can be accurately
inspected and gauged for wear or damage.
There are many commercially available cleaners
that quickly remove grease, oil and grime from
engine parts. When such a cleaner is used, follow
the manufacturer's instructions carefully. Make
sure all traces of the cleaner are removed before
the engine is reassembled and placed in opera-
tion. Even small amounts of these cleaners quickly
break down the lubricating properties of engine oil.
BASIC ENGINE TESTS
Fuel System Test
To determine if fuel is getting to the carburetor,
disconnect the fuel line at inlet to carburetor - if
fuel does not flow out of line, check system back
to tank for clogged lines, wrong (unvented) filler
cap, blocked filter screen, faulty fuel pump, etc. If
fuel is getting as far as the carburetor, remove
the spark plug, crank engine and check for fuel
inside combustion chamber. If no fuel is present
here, check for faulty carburetor.
Ignition System Test
To determine if the ignition system is good, re-
move the spark plug and place plug with side
electrode against cylinder head then crank engine
at sufficient speed to produce a good spark. If a
sharp, snappy spark is noted, this eliminates the
ignition system components as the cause, al-
though the ignition timing could be off.
If no spark or a weak spark is produced, check
the ignition system further. If points are pitted,
don't attempt to service them - replace points in
bad shape. Dirty points may be cleaned. A bad
condenser will cause premature failure of points.
Check the breaker push rod for evidence of bind-
ing or sticking - replace as needed. Condenser
can be tested on commercial tester per tester
manufacturer's instructions. Check ignition coil on
coil tester for continuity.
Crankcase Vacuum
A partial vacuum should exist in the crankcase
when the engine is operating at normal tempera-
tures. Pressure in the crankcase (usually caused
by a clogged or improperly assembled breather)
can cause oil to be forced out at oil seals, gas-
kets or other available spots.
Crankcase vacuum is best measured with a slack
tube manometer. The manometer included in the