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Maintenance; Carburetor - Husqvarna 159LEB Operator's Manual

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Your Normark product has been designed and
manufactured to specifications that reduce harmful
emissions. After the engine has used 8-10 tanks of fuel
the engine will be run-in. To ensure that it continues to run
at peak performance and to minimise harmful exhaust
emissions after the running-in period, ask your dealer/
service workshop (who will have a rev counter at their
disposal) to adjust your carburettor.
WARNING! The complete clutch cover
and gear housing must be fitted before
the machine is started, otherwise the
clutch may come loose and cause
personal injury.
The carburetor governs the engine's speed via the
throttle control. Air and fuel are mixed in the
carburetor. The air/fuel mixture is adjustable. Correct
adjustment is essential to get the best performance
from the machine.
The setting of the carburetor means that the engine is
adapted to local conditions, for example, the climate,
altitude, fuel and the type of 2-stroke oil.
The carburettor is fitted with two adjustment
L = Low speed jet
T = Idle adjustment screw
The fuel quantity in relation to the air flow permitted by
the throttle opening is adjusted by the L-needle.
Turning the needle clockwise gives a leaner fuel
mixture (less fuel) and turning it anticlockwise gives a
richer fuel mixture (more fuel). A lean mixture gives a
higher speed while a richer mixture gives a lower
The T-screw regulates the throttle setting at idle
speed. If the T-screw is turned clockwise this gives a
higher idle speed; turning it anti-clockwise gives a
lower idle speed.
Basic setting
The basic carburetor settings are adjusted during
testing at the factory. The basic setting is richer than
16 – English


the optimal setting and should be maintained for the
first few hours the machine is in use. The carburettor
should then be finely adjusted. Fine adjustment
should be carried out by a skilled technician.
CAUTION! If the cutting attachment rotates when the
engine is idling the idle adjustment screw T should be
turned anti-clockwise until the cutting attachment stops.
Rec. idle speed: 2700 rpm
Recommended max. speed: See the Technical data
Fine adjustment
When the saw has been "run-in" the carburettor
should be finely adjusted. The fine adjustment should
be carried out by qualified person. The L-needle is
adjusted first, then the idling screw T.
Before any adjustments are made, make sure that the
air filter is clean and the air filter cover is fitted. If you
adjust the carburettor when the air filter is dirty it will
result in a leaner mixture when the filter is finally
cleaned. This can lead to serious engine damage.
Carefully turn the L-needle to the centre position
between the fully screwed in and fully screwed out
Do not attempt to adjust the L-needle past the stop, as
this can result in damage.
Now start the machine according to the starting
instructions and let it warm up for 10 minutes.
CAUTION! If the cutting attachment rotates when the
engine is idling the idle adjustment screw T should be
turned anti-clockwise until the cutting attachment stops.
Low speed jet L
Try to find the highest idling speed, turning the low speed
needle L clockwise respectively counter-clockwise. When
the highest speed has been found, turn the low speed
needle L 1/4 turn counter-clockwise.
CAUTION! If the blades move while the engine is idling
the T screw should be turned anti-clockwise until they
WARNING! If the idle speed cannot be
adjusted so that the cutting attachment
stops, contact your dealer/service
workshop. Do not use the machine until
it has been correctly adjusted or



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