Maintenance; Carburettor - Husqvarna 325HS75 Operator's Manual

Carburettor

Your Husqvarna product has been designed and manufac-
tured to specifications that reduce harmful emissions.
After your unit has been run 8-10 tanks of fuel the engine
has broken in. To ensure that your unit is at peak perform-
ance and producing the least amount of harmful emissions
after break in, have your authorized servicing dealer, who has
a revolution counter at his disposal, to adjust your carburet-
tor for optimum operating conditions.
!
WARNING!
The complete clutch cover and gear must
be fitted before the machine is started,
otherwise the clutch may come loose and
cause injury.
Operation
• The carburettor governs
the engine's speed via the
throttle. Air/fuel is mixed
in the carburettor. The
air/fuel mixture is
adjustable. To take
advantage of the engine's
optimal output the
adjustment must be
correct.
• The setting of the
carburettor means that
the engine is adapted to
local conditions, for
example, the climate,
altitude, petrol and the
type of 2-stroke oil.
• The carburettor is equipped with three adjustment
possibilities:
H = High speed needle
L = Low speed needle
T = Idle speed adjuster screw
• The fuel quantity in relation to the air flow permitted by
the throttle opening is adjusted using the L and H-needles.
Turning the needles clockwise gives a leaner fuel mixture
(less fuel) and turning them anti-clockwise gives a richer
fuel mixture (more fuel). A leaner mixture gives high revs
while a richer mixture give less revs.
• The T-screw regulates the position of the throttle while
the engine is idling. Turning the screw clockwise gives a
higher idling speed while turning it anti-clockwise gives a
lower idling speed.
14
– English

MAINTENANCE

H
T
L
Basic setting
• The carburettor is set to its basic setting when test run at
the factory. The basic setting is richer than the optimal
setting and should be kept during the machine's first
working hours. Thereafter the carburettor should be finely
adjusted. Fine adjustment should be carried out by a skilled
technician.
NOTE! NOTE! If the blades move while the engine is idling
the T-screw should be turned anti-clockwise until the blades
stop.
Recommended idling speed is 2 700 rpm.
Recommended max. speed: See "technical data".
!
WARNING!
If the idling speed cannot be adjusted so
that the blades stop, contact your
service workshop. Do not use the
machine until it has been correctly
adjusted or repaired.
Fine adjustment
• When the machine has been "run-in" the carburettor should
be finely adjusted. The fine adjustment should be carried
out by qualified person. First adjust the L-jet, then the
idling screw T and then the H-jet.
Conditions
• Before any adjustments are made the airfilter should be clean
and the airfilter cover fitted. Adjusting the carburettor while
a dirty airfilter is in use will result in a leaner mixture when
the filter is finally cleaned. This can give rise to serious
engine damage.
• Carefully turn the L and H needle to the mid point between
fully turned in and fully turned out.
• Do not attempt to adjust the needles beyond the stops as
damage can occur.
• Now start the machine according to the starting instructions
and run it warm for 10 minutes.
NOTE! If the blades move, the T screw should be turned
counter-clockwise until the blades stop.
Low speed needle L
Try to find the highest idling
speed, turning the low speed
needle L clockwise respec-
tively counter-clockwise.
When the highest speed has
been found, turn the low
speed needle L 1/4 turn
counter-clockwise.
NOTE! If the blades move
when the engine is idling,
turn the idling speed screw T
counter-clockwise until the
blades stop.
L
+ 1/4
L