Husqvarna 390XP Workshop Manual page 33

14.3 Function
The carburettor operates differently in the following
modes:
• Cold start mode
• Idling mode
• Part throttle mode
• Full throttle mode
In the cold start mode (fig. 4) the choke valve (D) is fully
closed. This increases the vacuum in the carburettor so
that fuel is sucked more easily from all the diffuser jets
(E, F and G). The throttle valve (H) is partly open.
In the idling mode (fig. 5) the throttle valve (H) is closed.
Air is sucked in through an aperture in the throttle valve
and a small amount of fuel is supplied through the dif-
fuser jet (G).
In the part throttle mode (fig. 6 the throttle valve (H) is
partially open. Fuel is supplied through the diffuser jets
(F and G).
In full throttle mode (fig. 7 both valves are open and fuel
is supplied through all three diffuser jets (E, F and G).
Fig. 4 D E
Fig. 4 D E
Fig 4
Fig. 4 D E
Fig. 4 D E
Fig. 5 H
Fig. 5 H
Fig. 5 H
Fig 5
Fig. 5 H
Fig. 6 H
Fig. 6 H
Fig. 6 H
Fig 6
Fig. 6 H
Fig. 7
Fig. 7
Fig. 7
Fig. 7
Fig 7
Carburettor
F G
F G
F G
F G
G
G
G
G
F G
F G
F G
F G
E F G
E F G
E F G
E F G
English - 33