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SECTION 4
TROUBLESHOOTING
Engine Knocks
1. Low crankcase ail level.
2. Excessive engine load.
3. Old/improper fuel.
4. Internal wear or damage.
Engine Loses Power
. Low crankcase oil level.
. High crankcase oil level.
. Restricted air cleaner element.
. Dirt or water in fuel system.
Excessive engine load.
. Engine overheating.
. Faulty spark plugs.
. Carburetor Improperly adjusted.
. Low compression.
Engine Uses Excessive Amount Of Oii
1. Incorrect oil viscosity/type.
2. Clogged or improperly assembled breather
system.
3. Worn or broken piston rings.
4. Wom cylinder bores.
5. Wom valve stems and/or valve guides.
6. Crankcase being overfilled.
EXTERNAL ENGINE INSPECTION
Before cleaning or disassembling the engine, check
its external appearance and condition. This inspection
can give clues to what might be found inside the en-
gine (and the cause) once it is disassembled.
OOND
AYN
Г] Check for buildup of dirt and debris on the crank-
case, cooling fins, grass screen, and other exter-
nal surfaces. Dirt or debris in these areas are
causes of overheating.
CJ Check for obvious fuel and oil leaks, and dam-
aged components. Excessive oil leakage can in-
dicate a clogged or improperly assembled
breather, worn or damaged seals and gaskets, or
loose or improperly torqued fasteners.
O Check the air cleaner cover, element cover, and
air cleaner base for damage or indications of im-
proper fit and seal. Also check the seals on the
air cleaner cover wing nuts. Missing or damaged
seals could allow dirt to enter the engine.
О Check the air cleaner element. Look for holes,
tears, cracked or damaged sealing surfaces, or
other damage that could ailow dirt to enter the
engine. Also note if the element is clogged or re-
Stricted. These could indicate that the air cleaner
has been under serviced.
О Check the carburetor throat for dirt. Dirt in the
throat is further indication that the air cleaner is not
functioning properly.
O Check the oil level. Note if the oil level is within
the operating range on the dipstick, or if it's low or
overfilled.
О 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 loca-
tion away from the workbench. Be sure to
allow ample time for complete drainage.
Sludge is a natural by-product of combustion; a
small accumulation is normal. Excessive sludge
formation could indicate that the oil has not been
changed as recommended, an incorrect type or
weight of oil was used, over rich carburetor set-
tings, and weak ignition, to name a few.
CLEANING THE ENGINE
After inspecting the extemal condition of the engine,
clean it thoroughly before disassembling. Also clean
individua! components as the engine is disassembled.
Only clean parts can be accurately inspected and
gauged for wear or damage.
There are many comrnercially available cleaners that
Quickly remove grease, oil, and grime from engine
parts. When such a cleaner is used, follow the manu-
facturer's instructions carefully. Make sure all traces
of the cleaner are removed before the engine is reas-
sembled and placed into operation. Even small
amounts of these cleaners quickly break down the
lubricating properties of engine oil.
4.2
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