Husqvarna 129C Workshop Manual page 42

Repair Instructions
Fine adjustment
Fine adjustment of the carburettor should be
carried out after the engine has been "run-in".
It is important that the air filter is clean and that
the carburettor cover is fitted when adjusting the
carburettor. The engine must be run warm at full
throttle. Run the engine for 4 to 5 minutes to make
sure it is warm.
Then adjust the carburettor needles in two steps as
follows:
First adjustment
1. Turn the L needle clockwise until the top idle
speed is reached. If the trimmer head then
rotates, reduce the speed by turning the idle
screw (T) anticlockwise until it stops rotating.
2. Turn the H needle at full throttle to the position
where the engine starts running unevenly (four-
stroking).
3. Stop the engine.
Second adjustment
1. Start the engine (still warm).
2. Turn the L needle anticlockwise so that the
speed drops by 500 rpm.
3. Stop the engine.
4. Turn the H needle a 3/4 turn clockwise.
5. Then adjust the idling speed to 2,900 rpm by
turning the idle screw (T).
42
- English
Idling speed T-screw
Let the engine idle for about 30 seconds or until
the speed has stabilized. Adjust the idling speed
T-screw until the engine idles without stopping.
• Turn the screw clockwise if the engine stops.
• Turn the screw anticlockwise to lower the speed.
Correctly adjusted carburettor
A correctly adjusted carburettor means that the
engine accelerates without hesitation and it four-
strokes a little at full throttle.
• The cutting equipment must not rotate while
idling.
• A too lean adjusted L-needle can cause starting
difficulties and poor acceleration.
• A too lean adjusted H-needle results in lower
power, poor acceleration and/or damage to the
engine.
• A too rich setting of the "L" and "H" needles give
acceleration problems or a too low working
speed.