Husqvarna 333R, Руководство по ремонту

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3
Fuel system
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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 accelera-
tion 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.
The H and L needles on the carburettor can be adjusted within extremely tight
limits, to among others, comply with the stringent demands with regard to the
hydrocarbon and nitrogen oxide content in the exhaust fumes.
The carburettor needles on these carburettors are blocked with locking plugs.
To carry out adjustment when replacing needles or the entire carburettor the engine
must be under load. This is achieved by fitting the trimmer head T35 with the
specified length and diameter of trimmer cord. Consequently, the stated speed will
be much lower than with ”normal” carburettor adjustment when the engine may run
freely.
After replacing the needles or the entire carburettor on a CARB-EPA approved
engine, adjustment must be carried out according to the instructions below.
The combiguard or trim guard must be fitted when adjusting the H-needle.
NOTE!
A tachometer should always be used to find 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.
High speed needle H
The high speed needle H affects the engine power, speed,
temperature and fuel consumption. If the high speed needle
is set too lean (screwed in too far) the engine speed will be
too high and cause engine damage. Do not let the engine
run at full speed for more than 10 seconds.
Apply full throttle and turn the high speed needle H very
slowly clockwise until the engine slows down.
Note the engine should be loaded during the adjustment of
high speed needle H. Fit the trimmer head T35 (2.7 mm
cord). The cord length should be as standard, i.e. reach the
knife on the trimmer guard.
Now turn the needle very slowly anticlockwise until the
engine starts to run unevenly. Now turn the needle slowly
clockwise until the engine runs smoothly.
NOTE!
An accredited dealer/service workshop that has a
tachometer should be contacted in order to obtain an
optimal carburettor setting.