Husqvarna 335RJX series, Operator'S Manual

Page: 20 / 36

MAINTENANCE
20 – English
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.
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: See the Technical data section.
Recommended max. speed: See the Technical data
section.
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.
Conditions
• 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 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 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 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 cutting attachment rotates when the
engine is idling the idle adjustment screw T should be turned
anti-clockwise until the cutting attachment stops.
!
WARNING! The complete clutch cover and
shaft must be fitted before the machine is
started, otherwise the clutch can come
loose and cause personal injury.
H
L
T
!
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