Husqvarna 243RJ Workshop Manual page 27

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 recommen-
ded 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:
Model Carburettor
model
WT 841D
243 RJ
WT 795F
253 RJ
253 RJ WT 795G
The following conditions apply to all carburettor settings in order to achieve the correct
result:
• Defect-free spark plug with correct electrode gap.
• Defect-free air fi lter. Clean and correctly fi tted.
• There should be no leaks between the cylinder and the distance piece and the car-
burettor and the distance piece. Check the screws are tight.
• The fuel fi lter should be clean.
• The exhaust port (muffl er and cylinder) should not be completely or partially clogged.
• The cutting attachment (blade or trimmer head with respective cord) must be fi tted.
• Correct fuel quality, minimum 89 octane.
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 540 06 82-01 to dismantle the locking plugs so the needles can be screwed
out, e.g. for replacing or cleaning.
502 71 14-01
NOTE!
The rev counter must always be used for optimal settings.
The recommended maximum speed must not be exceeded.
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.
L-nål H-nål
3 3/4 ± 1/2 1 1/8 ± 1/2
2 1/8 ± 1/2 3 1/8 ± 1/2
2 1/8 ± 1/2 2 7/8 ± 1/2
501 60 02-03
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 (12,500 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 splutters.
3
504 62 29-01
25