Carburettor - Pressure Testing - Husqvarna 340 Workshop Manual

Repair instructions
Carburettor – 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 can also be performed for trouble-
shooting before dismantling.
Carry out the test as follows:
• Screw in the high and low speed jet screws and
back them off one turn.
• Connect pressure tester 502 50 38-01 to the
carburettor fuel inlet.
• Lower the carburettor into a beaker of water.
• Pump up the pressure to 50 kPa (0.5 bar) and
clamp the pump tube.
• There should be no leakage. If leakage occurs,
refer to the table below.
Leakage
Diffuser jets
In impulse tube
Ventilation hole above
metering unit
34
– English
Fault lies in
Needle valve
Pump diaphragm
Control diaphragm
Carburettor – refitting
NOTE!
Cleanliness is very important when reas-
sembling the carburettor. Tiny particles of
dirt can cause operating problems.
1
Align the inlet manifold 503 86 63-01 with the cut-
out in the carburettor flange 503 86 64-01 and
make sure the inlet manifold is correctly seated.
Make sure the impulse tube is correctly seated in
the impulse channel on the cylinder.
Fit the perforated brass support ring in the inlet
manifold.
2
Fit stop plate 502 54 17-01 between the carburet-
tor flange and the insulating plate.