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• The carburettor has three adjustment controls:
- L = Low speed jet
- H = High speed jet
- T = Idle adjustment screw
• 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 settings are H = 1 turn and L =
1 turn.
To provide the engine’s components with good
initial lubrication (during running in) the carburettor should
be set for a richer fuel mixture for the first 3-4 hours that
the chain saw is in use. To do this, adjust the fast idle
speed to 600-700 rpm below the recommended
maximum fast idle speed.
If you are unable to check the fast idle speed using a
tachometer the H-jet should not be set for a leaner
mixture than given in the basic settings. The
recommended maximum fast idle speed must not be
exceeded.
CAUTION! If the chain rotates while idling
the T-screw must be turned anti-clockwise until the
chain stops.
Fine adjustment
When the machine has been ”run-in” the carburettor
should be finely adjusted. The fine adjustment should be
carried out by a qualified person. First adjust the L-jet,
then the idling screw T and then the H-jet.
The recommended engine speeds are as follows:
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.
• Carefully turn the L and H-jets clockwise as far as they
will go. Now turn the jets one turn anti-clockwise. The
carburettor is now set to H = 1 and L = 1.
• Now start the machine according to the starting
instructions 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 using the idle adjustment screw T, if
it is necessary to readjust. First turn the idle adjustment
screw T clockwise until the cutting attachment starts to
rotate. Then turn the screw anticlockwise until the cutting
attachment stops. The idle speed is correctly adjusted
when the engine will run smoothly in every position. The
idle speed should also be well below the speed at which
the cutting attachment starts to rotate.
High speed jet H
• The high speed jet H influences the power and engine
speed of the machine. If the high speed jet is set too
rich (H-jet screwed in too far) the machine will over-rev
and this will damage the engine. Run the machine at
full throttle for about 10 seconds. Then turn the H-jet
1/4 turn anti-clockwise. Run the machine at full throttle
for another 10 seconds or so and listen to the
difference in the fast idle speed. Repeat this
procedure with the H-jet turned a further 1/4 turn anti-
clockwise.
Max. fast idle speed, rpm
Idle speed, rpm
385XP/XPG
12500 2700
390XP/XPG
13500 2700
L
H
T
!
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.
L
+ 1/4
H