18 – English
MAINTENANCE
Carburettor
Your Husqvarna product has been designed and
manufactured to specications 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 rst few hours the
machine is in use. The carburettor should then be nely
adjusted. Fine adjustment should be carried out by a
skilled technician.
CAUTION! If the blades move while the engine is idling the T
screw should be turned anti-clockwise until they stop.
Rec. idle speed 2700 rpm
Recommended max. speed: See the Technical data section.

Fine adjustment

When the machine has been ”run-in” the carburettor
should be nely adjusted. The ne adjustment should be
carried out by a qualied person. First adjust the L-jet,
then the idling screw T and then the H-jet.

Conditions

Before any adjustments are made, make sure that the air
lter is clean and the air lter cover is tted. If you adjust
the carburettor when the air lter is dirty it will result in a
leaner mixture when the lter is nally cleaned. This can
lead to serious engine damage.
Carefully turn both jets, L and H, so that they are midway
between fully screwed in and fully screwed out.
Do not attempt to adjust the L and H jets beyond either
stop as this could cause damage.
Now start the machine according to the starting
instructions and let it warm up for 10 minutes.
CAUTION! If the blades move while the engine is idling the T
screw should be turned anti-clockwise until they stop.

Low speed jet L

Try to nd the highest idle speed by turning the low speed jet
L clockwise then anti-clockwise. When the highest speed has
been found, turn the low speed jet L 1/4 turn anti-clockwise.
CAUTION! If the blades move while the engine is idling the T
screw should be turned anti-clockwise until they stop.
!
WARNING! The complete clutch cover and
shaft must be tted before the machine is
started, otherwise the clutch can come loose
and cause personal injury.
!
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 repaired.
L
+ 1/4