Husqvarna K770 SmartGuard, Workshop Manual

Page: 33 / 76

Hose (A) is connected to the carburetor. When you push
the air purge bulb, a vacuum is caused and fuel fills the
fuel chamber. When the fuel chamber is fully filled,
unwanted fuel is pushed to the tank through return hose
(B). This means that the fuel level in the carburetor does
not become too high.
6.5.9 To do a test of the air purge bulb
A Husqvarna test instrument for fuel lines and check
valves is necessary. Refer to
Servicing tools overview
on page 11
If the air purge bulb does not fill with fuel when you push
it, do this procedure.
1. Connect the test instrument to the hose from the air
purge bulb.
2. Set the test instrument for vacuum test.
3. Push the air purge bulb to increase the pressure to
0.3–0.5 bar.
If the pressure can be increased to 0.3–0.5 bar, the air
purge bulb and hose connection are not damaged. Then
it is necessary to look for faults in the other components
of the fuel system.
6.5.10 To remove the air purge bulb
1. Remove the return hose and carburetor hose from
the air purge bulb.
2. Push the snap lock with pliers and push the air
purge bulb out.
6.6 Carburetor
6.6.1 To remove the carburetor from the inlet
system
1. Remove the service filter.
2. Clean the outer parts of the carburetor before you
remove it from the inlet system.
1453 - 001 - 02.04.2020 Repair and servicing - 33