Carburettor Settings - Husqvarna 326R Workshop Manual

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Fuel system

Carburettor settings

WARNING!
When testing the engine in connection with carburettor
adjustment, the clutch and clutch cover must be mounted
together with the shaft and angle gear under all circumstances
Otherwise there is a risk of the clutch becoming loose resulting in
serious personal injury.
Function
The carburettor has the task of supplying a combustible fuel/air mixture to the
cylinder.
The amount of this mixture is controlled by the throttle.
The mixture's composition of fuel and air is controlled by means of the adjustable
"H" and "L" needles.
The needles must be correctly adjusted in order for the engine to give maximum
power at different speeds, run steadily while idling and to react quickly when
accelerating.
The setting of the carburettor can vary a little depending on the humidity,
temperature and air pressure.
L = Low speed needle
H = High speed needle
T = Idle adjustment screw
• The fuel quantity in relation to the air flow permitted by the throttle opening is
adjusted by the L and H jets. Turning the needles clockwise gives a leaner fuel
mixture (less fuel) and turning them anticlockwise gives a richer fuel mixture
(more fuel). A leaner mixture gives higher revs while a richer mixture gives 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
anticlockwise gives a lower idling speed.
Assembly of the throttle is done in the
reverse order as set out for
dismantling.
Position the parts in the left-hand
throttle half.
Ensure the return spring (A) is facing
the right way.
Check that the throttle cable and the
short-circuit cable are pressed correctly
down in their channels so that they are
not pinched when the two throttle
halves are screwed together.
Do not forget to put the vibration
element (B) in position before the
throttle halves are put together.
Lubricate the vibration element with
soapy water. This facilitates fitting the
throttle on the shaft.
Fit together the throttle halves using
the 5 screws, but do not tighten them
fully before the throttle has been
positioned on the shaft.
Assemble the remaining parts in the
reverse order as set out for dis-
mantling.