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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, Basic settings, Fine adjustment
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 oper
ating conditions, e.g. climate,
altitude, petrol and the type of 2-stroke oil.
• The carburettor has two adjustment controls:
- L = Low speed jet
- T = Idle adjustment screw (Maximum speed is
controlled b
y a fixed jet/electronic speed governor).
• The amount of fuel that is mixed with the air admitted
b
y the throttle opening is adjusted using the low speed
jet. If this is turned clockwise it gives a leaner air/fuel
mixture (less fuel) and if it is turned anti-clockwise it
gives a richer air/fuel mixture (more fuel). A leaner
mixture gives a higher engine speed, while a richer
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 settings and running in
The basic carburettor settings are adjusted during testing
at the factory.
The basic setting is: L = 1 turn.
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.
The recommended engine speeds are as follows: Idle
speed 2500 rpm
Changing the type of fuel
Fine tuning may be required if the chain saw, after
changing the type of fuel, performs differently with regard
to starting, acceleration, maximum speed, etc.
Conditions
• Before any adjustments are made the air filter should
be clean and the cylinder cover fitted. Adjusting the
carburettor while a dirty air filter is in use will result in
a leaner mixture next time the filter is cleaned. This
can give rise to serious engine damage.
• Turn the low speed jet carefully clockwise until it
bottoms
. Now turn it one turn anti-clockwise. The
carburettor is now set to L = 1.
• Now start the machine according to the starting
instr
uctions and let it warm up for 10 minutes.
CAUTION! If the chain rotates while idling the T-
screw must be turned anti-clockwise until the
chain stops.
• Place the machine on a flat surface so that the bar
points away from you and so that the bar and chain do
not come into contact with the surface or other
objects.
Low speed jet L
Try to find 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 chain rotates while idling the T-screw
must be turned anti-clockwise until the chain stops.
Fine adjustment of the idle speed T
Adjust the idle speed with the T-screw. If it is necessary to
re-adjust, turn the T-screw clockwise while the engine is
running, until the chain starts to rotate. Then turn anti-
clockwise until the chain stops. When the idle speed is
correctly adjusted the engine should run smoothly in
every position and the engine speed should be safely
below the speed at which the chain starts to rotate.
!
WARNING! Do not start the chain saw
unless the bar, chain and clutch cover
(chain brake) are fitted, otherwise the
clutch may come loose and cause
personal injury.
!
WARNING! Contact your servicing
dealer, if the idle speed setting cannot be
adjusted so that the chain stops. Do not
use the chain saw until it has been
properly adjusted or repaired.