Husqvarna 250PS - Manual (Page 21)

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21
MAINTENANCE
Air filter
The air filters must be regularly cleaned from dust and dirt in
order to avoid:
• Carburettor malfunctions
• Starting problems
• Engine power reduction
• Unnecessary wear on the engine parts
• Abnormal fuel consumption
If the engine is low on power, difficult to start or runs
poorly at idling speed, always check the spark plug first.
If the spark plug is dirty, clean it and check the electrode gap.
Readjust if necessary. The correct gap is 0.5 mm (.020"). The
spark plug should be replaced after about one month or
earlier if the electrodes are badly eroded.
IMPORTANT!
Always use the recommended spark plug type. Wrong type
may ruin the piston/cylinder.
Spark plug
The spark plug condition is
influenced by:
• An incorrect carburettor
setting.
• An incorrect fuel mixture
(too much or faulty oil).
• A dirty air filter.
These factors cause deposits
on the spark plug
electrodes, which may result
in malfunction and starting
difficulties.
Muffler
The muffler is designed in
order to reduce the noise
level and to direct the
exhaust gases away from the
operator. The exhaust gases
are hot and can contain
sparks, which may cause fire
if directed against dry and
combustible material.
Some mufflers are equipped
with a special screen. If your
saw has this type of muffler,
you should clean the screen
at least once a week. This is
done with a wire brush. The
screen must be replaced, if
damaged. The engine will
be overheated, if the screen
is clogged. This results in
damage on the cylinder and
the piston.
CAUTION!
Never use a pruner with a
clogged or defective muffler.
Cleaning/change
Clean the filter after 25
hours or more regularly if
operating conditions are
exceptionally dusty.
Dismantle the air filter
cover and remove the air
filters. Wash in clean, warm
soapy water.
Ensure that the filters are
dry before refitting.
An air filter used for a long
period of time can never be
cleaned completely.
Therefore it is necessary to
replace the filter from time
to time with a new filter.
A damaged air filter must
always be replaced.
Correctly adjusted carburettor
A correctly adjusted carburettor implies that the engine
accelerates without a pause and that the engine splutters
slightly at full throttle. Also, the chain does not rotate at
idling speed. An excessively lean setting for the L-nozzle can
result in starting difficulties and poor acceleration. An
excessively lean H-nozzle setting results in a lower output,
poor acceleration, and/or damage to the engine.
An over rich setting of both L and H results in acceleration
problems or excessively low working revs.
0,5 mm