Husqvarna 241R Workshop Manual page 27

3
H
26
Fuel system
Fine adjustment after running-in
After the running-in period it may be necessary to fi ne adjust the carburettor nozzles,
usually to get a leaner fuel/air mix.
The basic factory setting is somewhat "richer" than the optimal setting (fast idle speed is
600 - 800 rpm below recommended maximum revs) and shall be maintained for the fi rst
hours of engine operation.
To carry out a correct adjustment, the engine must be under load during adjustment.
This is achieved by fi tting trimmer T35 with specifi ed length and diameter on the trimmer
thread (see below).
The combiguard or trim guard must be fi tted when adjusting the H-needle.
NOTE!
Warm up the engine 4 minutes at 9,500 - 10,000 rpm before beginning
carburettor adjustment.
• 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.
• At full throttle, the H-needle shall have a setting so that the engine is almost
splutters.
• 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.
540 06 82-01
531 00 48-63
Limited adjustments of the jet needles can be made with a
screwdriver without having to dismantle the stop plugs. The
needles can be turned max. a quarter turn in either direction.
If the carburettor cannot be adjusted suffi ciently, the jet nee-
dles can be released if the stop plugs are pulled out until they
are level with the carburettor housing or removed completely
using the tool 540 06 82-01 (left-hand threads).
Use the special screwdriver 531 00 48-63, which is thin
enough to be stuck into the hole in the stop plug and the
groove in the jet needle.
Push in the stop plugs in the carburettor housing after com-
pleted adjustment. Also see "Assembly of stop plugs" below.