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English – 17
Carburettor
Your Husqvarna 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.
Function
The carburettor governs the engine’s speed via the
throttle control. Air and fuel are mixed in the carburettor.
The air/fuel mixture is adjustable. Correct adjustment is
essential to get the best performance from the machine.
Adjusting the carburettor means that the engine is
adapted to local operating conditions, e.g. climate,
altitude, petrol and the type of 2-stroke oil.
The carburettor has three adjustment controls:
• L = Low speed jet
• H = High speed jet
• T = Idle adjustment screw
The L and H-jets are used to adjust the supply of fuel to
match the rate that air is admitted, which is controlled with
the throttle. If they are screwed clockwise the air/fuel ratio
becomes leaner (less fuel) and if they are turned anti-
clockwise the ratio becomes richer (more fuel). A lean
mixture gives a higher engine speed and a rich mixture
gives a lower engine speed.
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 carburettor settings are adjusted during testing
at the factory. The basic setting is richer than 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.
Adjustment of the idle speed
Before any adjustments are made, make sure that the air
filter is clean and the air filter cover is fitted.
Adjust the idle speed screew T clockwise respectively
anti-clockwise until an idle speed of 2300 rpm is reached.
Muffler
The muffler is designed 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.
The muffler is equipped with a special spark arrestor
mesh. The spark arrestor mesh should be cleaned once
a month. This is best done with a wire brush.
To remove the spark arrestor mesh proceed as follows:
Remove the screws to the capillary tube and exhaust
pipe.
L
H
T