Husqvarna R135 Workshop Manual page 34

Fine adjustment
Fine adjustment of the carburettor should be carried out after
the engine has been "run-in". It is important that the air fi lter is
clean and that the carburettor cover is fi tted when adjusting the
carburettor.
The engine must be run warm at full throttle which is approx.
11,000 rpm (electronic speed limitation). 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 rotat-
ing.
2. Turn the H needle at full throttle to the position where the
engine starts running as a 4-stroke.
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 (half a turn for models
135 and 336).
5. Then adjust the idling speed to 2,900 rpm by turning the idle
screw (T).
After adjustments are made, the sleeve on each needle must be
fi tted so that they cannot be turned anticlockwise ("richer" fuel-air
mix).
H
Fuel system
NOTE!
If the cutting equipment rotates while idling the
T-screw should be turned anticlockwise until it stops.
A tachometer should always be used to fi nd the
optimal setting.
Idling speed T-screw
Let the engine idle for about 30 seconds or until the speed
has stabilised. 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 ac-
celerates 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 diffi culties
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 accelera-
tion problems or a too low working speed.
531 00 48-63 502 71 14-01
Using a screwdriver 531 00 48-63 it is possible to make
small adjustments to the jet needles without the need of
removing the locking plugs.
Use the tool 504 62 29-01 to dismantle the locking plugs
(left-hand threads) so the needles can be screwed out,
e.g. for replacing or cleaning.
504 62 29-01
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