Husqvarna 570 Workshop Manual page 36

7. Fit the control diaphragm (B) with gasket and cover
(A) on the metering unit. See fig. 17.
8. Fit the axle on the air shutter (L) and connect the
throttle actuator rod (N) in parallel with the ordinary
throttle valve. The valve housing (P) is secured in
the carburettor using two screws.
The gasket between the carburettor and the valve housing
is, if the saw has the designation XPG, replaced by a
carburettor heater.
9. Carry out a pressure test.
Pressure testing
Pressure testing should be carried out with the
carburettor fully assembled. Testing should always be
carried out after the carburettor has been repaired, but
it can also be carried out as trouble shooting before
dismantling the carburettor.
See fig. 19 and carry out the test as follows:
1. Unscrew the high and low speed screws one turn
from closed position.
2. Connect pressure tester to the carburettorʼs fuel
intake.
3. Lower the carburettor into a beaker of water.
4. Pump up the pressure to 50 kPa (0.5 bar).
5. No leakage is permitted. If a leakage occurs refer to
the table below.
Leakage at
Diffuser jets
Leakage in impulse tube
Ventilation hole
on metering unit.
36 – English
CARBURETTOR
Fault with
Needle valve
Pump diaphragm
Control diaphragm
A
B
Fig. 17
L
N
A
Fig. 18
Fig. 19
P