Carburettor Settings - Husqvarna 243RJ Workshop Manual

3
24
Fuel system
13. Fit the distance piece onto the cylinder.
502 71 27-02
14. Fit the "rubber connection".
15. Push the fuel return hose down into
the tank.
16. Fit the carburettor and other parts in
the reverse order as set out for dis-
mantling.

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 fl ow 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 lea-
ner 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.
13. Check the impulse channel (A) in the
distance piece is open.
Replace gasket where necessary and
fi t the distance piece onto the cylinder
using the 3 screws.
14. Fit the "rubber connection" onto the
distance piece.
NOTE!
The rubber connection is
assymmetrical so take care when
fi tting to ensure it is fi tted onto
the distance piece as shown in the
illustration.
15. Push the fuel return hose down into
the tank.
16. Fit the carburettor and other parts in
the reverse order as set out for dis-
mantling.
NOTE!
Do not forget the lower screw (into
the fuel pump blower) when fi tting
the air fi lter.