Husqvarna 225AI15/AI25 manual Maintenance, Carburettor

MAINTENANCE

Carburettor

Your Husqvarna product has been designed and manufac- tured to specifications that reduce harmful emissions. After your unit has been run 8-10 tanks of fuel the engine has broken in. To ensure that your unit is at peak perform- ance and producing the least amount of harmful emissions after break in, have your authorized servicing dealer, who has a revolution counter at his disposal, to adjust your carburet- tor for optimum operating conditions.

!WARNING!

The complete clutch cover and gearbox must be fitted before the machine is started, otherwise the clutch may come loose and cause personal injury.

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 and should be kept during the machine’s first working hours. Thereafter the carburettor should be finely adjusted. Fine adjustment should be carried out by a skilled technician.

NOTE! If the cutting attachment rotates/moves while the engine is idling the T-screw should be turned anti-clockwise until the cutting attachment stops.

Recommended idling speed is: 2 700 rpm.

Recommended max. speed: See “Technical data”.

WARNING!

If the idling speed cannot be adjusted so

! that the cutting attachment stops,

contact your service workshop. Do not

Operation

•The carburettor governs the engine’s speed via the throttle. Air/fuel is mixed in the carburettor. The air/fuel mixture is adjustable. To take advantage of the engine’s optimal output the adjustment must be correct.

•The setting of the carburettor means that the engine is adapted to local conditions, for example, the climate, altitude, petrol and the type of 2-stroke oil.

L	T
H

use the machine until it has been

correctly adjusted or repaired.

Adjusting the idle speed, T

Adjust the idle speed with screw T, if it is necessary to readjust. First turn the idle speed adjusting screw T clockwise until the cutting attachment begins to move. Then turn the screw anticlockwise until the cutting attachment stops. The idle speed is correctly adjusted when the engine runs smoothly in any position. There should also be a good margin to the

•The carburettor is equipped with three adjustment possi- bilities:

H = High speed needle L = Low speed needle

T = Idle speed adjuster screw

•The fuel quantity in relation to the air flow permitted by the throttle opening is adjusted using the L and H-needles. Turning the needles clockwise gives a leaner fuel mixture (less fuel) and turning them anti-clockwise gives a richer fuel mixture (more fuel). A leaner mixture gives high revs while a richer mixture give less revs.

•The T-screw regulates the position of the throttle while the engine is idling. Turning the screw clockwise gives a higher idling speed while turning it anti-clockwise gives a lower idling speed.

engine speed at which the cutting attachment begins to move.

CAUTION! Contact your servicing dealer, if the idle speed setting cannot be adjusted so that the cutting attachment stops. Do not use the machine until it has been properly adjusted or repaired.

Correctly adjusted carburettor

A correctly adjusted carburettor means that the machine accelerates without hesitation and the machine 4-cycles a little at max. speed. Furthermore, the cutting attachment must not move at idling. If the setting of the low speed needle L is too lean it may cause starting difficulties and poor acceleration. If the setting of the high speed needle H is too lean it causes lower power = less capacity, poor acceleration and/or damage to the engine.

An excessively rich adjustment of the two speed needles L and H gives acceleration problems or too low working speed.

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