Husqvarna 129C Workshop Manual page 60

Troubleshooting
Acceleration/Deceleration
Engine does Fuel filter blocked
not accelerate The fuel hose blocked
Air in fuel ducts
Vacuum pulse leakage
Vacuum pulse duct blocked
Loose screw(s) on the pump
cover
Faulty pump diaphragm
The needle valve faulty
Carburettor is not fitted correctly
Needle valve's lever arm
damaged
Needle valve's lever arm too low
Needle valve's lever arm does
not work correctly
Needle valve's spring is not fitted
correctly
Control diaphragm is damaged
Needle valve jams
Engine Faulty pump diaphragm
stops when Needle valve's lever arm too high
decelerating Needle valve's lever arm does
not work correctly
Needle valve worn
Foreign object in the needle
valve guide
Poor Faulty heat insulation seal
acceleration
capacity
8.2 Troubleshooting methods
In addition to the faults described in the above
table, troubleshooting can be carried out on
specific components or sub-systems of the
trimmer. The various procedures are described in
the relevant chapters, see the contents page, as
follows:
• Checking the ignition spark
• Pressure testing the carburettor
60
- English
High speed
Poor Fuel filter blocked
performance The fuel hose blocked
at high speed Air in fuel ducts
Incorrect/poor fuel
Vacuum pulse leakage
Vacuum pulse duct blocked
Loose screw(s) on the pump
cover
Faulty pump diaphragm
The needle valve faulty
Carburettor is not fitted correctly
Needle valve's lever arm
damaged
Needle valve's lever arm does
not work correctly
Needle valve's spring is
deformed
Needle valve's spring is not fitted
correctly
Control diaphragm is damaged
Faulty seal of control diaphragm
Needle valve worn
Foreign object in the needle
valve guide