Husqvarna 545RX Workshop Manual page 28

3
Use the 502 71 14-01 tachometer to
check the speed.
•
502 71 14-01
•
530 03 55-60
501 60 02-03
26
Fuel system
Basic setting
The carburettor is set to its basic setting when test run at the factory. The basic setting is
"richer" than the optimal setting (fast idle speed is 600–800 rpm under the recommend-
ed max. speed) and should be kept during the engine's fi rst working hours. Thereafter
the carburettor should be fi ne tuned.
The default setting is:
H = 1.1 revolution open
L = 0.9 revolution open
Fine adjustment
Fine adjustment of the carburettor should be carried out after the engine has been "run-
in".
• The air fi lter should be clean and the cylinder cover fi tted when all adjustments are
made.
First adjust the L-needle, then the H-needle and fi nally the idling speed's T-screw.
Idling speed = 2,800 rpm.
• Since the ignition system is limited in terms of rpm, the pre-programmed fast idle
speed (12,000 – 13,000 rpm) cannot be exceeded even if the H-needle is screwed
inwards. The risk in this case is still that the engine breaks down as a result of a too
lean fuel/air mix.
• At full throttle, the H-needle shall have a setting so that the engine is almost splut-
ters.
Carefully screw in (clockwise)
the L- and H-jets until they bot-
tom. Now unscrew (anti-clockwi-
se) the jets to the default setting.
Use tool 530 03 55-60.
Start the engine and run warm
for 5 minutes.
NOTE!
A tachometer should always be used to fi nd the optimal
setting.
The recommended max. speed must not be exceeded.
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 acceler-
ates without hesitation and it "splatters" a little at full throttle.
• 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 ac-
celeration 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.
NOTE!
If the cutting equipment rotates while idling the T-screw
should be turned anticlockwise until it stops.