Husqvarna Essential Maintenance for Your Chainsaw with Focus on Carburettor Settings
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MAINTENANCE

Carburettor

Functioning, Basic setting, Final setting

!WARNING! Do not start the saw without the bar, chain and clutch cover (chain brake) assembled. If you do, the clutch might come loose and cause severe injuries.

Operation

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

•Adjusting the carburettor means the engine is adapted to local operating conditions, e.g. climate, altitude, petrol and the type of 2-stroke oil used.

• The carburettor has three adjustment possibilities: L = Low speed jet.

H = High speed jet.

T = Adjustment screw for idling.

•The fuel quantity required in relation to the air flow, provided by opening the throttle, is adjusted by the L and H-jets. If they are screwed clockwise the air/fuel ratio becomes leaner (less fuel) and if they are turned anti-clockwise the ratio becomes richer (more fuel). A leaner mixture gives a higher engine speed and a richer mixture give a lower engine speed.

•The T screw regulates the idling speed. If the screw T is turned clockwise this gives a higher idling speed; anti- clockwise a lower idling speed.

Basic setting and running in

The carburettor is adjusted to a basic setting when the saw is tested at the factory.

254XP: The basic setting is: H = 1 1/2 turns respective

L= 1 1/4 turns.

257:The basic setting is: H = 1 turns respective

L= 1 turns.

262XP: The basic setting is: H = 1 turns respective L = 1 turns.

To provide the engine’s components with a good level of lubrication (running in) the carburettor should be set for a richer fuel mixture for the first 3-4 hours of operating. To obtain this adjust the overspeed 6-700 rpm under the recommended max. overspeed.

If you do not have the possibility to check the overspeed using a tachometer the H-jet should not be set for a leaner mixture than that stated for the basic setting.

The recommended overspeed should not be exceeded. NOTE! If the chain rotates while idling the T screw should be adjusted anti-clockwise until it stops.

Fine adjustment

•When the saw has been ”run-in” the carburettor should be finely adjusted. The fine adjustment should be carried out by qualified person. First adjust the L-jet, then the idling screw T and then the H-jet.

The following engine speed applies:

 

Max. overspeed

Idling speed

254XP:

13.800

rpm

2.500 rpm

257:

13.500

rpm

2.500 rpm

262XP:

13.500

rpm

2.500 rpm

Conditions

•Before any adjustments are made the air filter should be clean and the cylinder cowling fitted. Adjusting the carburettor while a dirty air filter is in use will result in a leaner mixture when the filter is finally cleaned. This can give rise to serious engine damage.

•Carefully turn the L and H-jets clockwise to the bottom. Now

turn the jets one turn anti-clockwise. The carburettor is now set to H = 1 and L = 1.

•Now start the saw according to the starting instructions and run it warm for 10 minutes.

NOTE! If the chain rotates the T screw should be turned anti-clockwise until the chain stops.

•Place the saw on a flat surface so that the bar points away from you and so that the bar and chain do not come into contact with the surface or other objects.

Low speed needle L

 

 

 

+ 1/4

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Try to find the highest idling

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

speed, turning the low speed

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

needle L clockwise

 

 

 

 

 

 

 

 

 

 

 

 

respectively counter-

 

 

 

 

 

 

 

 

 

 

 

 

clockwise. When the highest

 

 

 

 

 

 

 

 

 

 

 

 

speed has been found, turn

 

 

 

 

 

 

 

 

 

 

 

 

the low speed needle L 1/4

 

 

 

 

 

 

 

 

 

 

 

 

turn counter-clockwise.

L

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

NOTE! If the chain rotates in

 

 

 

 

 

 

 

 

 

 

 

 

the idling position, turn the idling speed screw counter- clockwise until the chain stops.

Final setting of the idling speed T

Adjust the idling speed with the screw T. If it is necessary to re- adjust, first turn the idle speed adjusting screw T clockwise, until the chain starts to rotate. Then turn, counter-clockwise until the chain stops. A correctly adjusted idle speed setting occurs when the engine runs smoothly in every position. It should also be good margin to the rpm when the chain starts to rotate.

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

High speed needle H

 

The high speed needle H

 

influences the power of the

 

saw. A too lean adjusted high

 

speed needle H (high speed

 

needle H closed too much)

 

gives overrevs and damages

 

the engine. Let the saw run at

 

full speed for about 10

 

seconds. Thereafter, turn the

H

high speed needle H 1/4 turn

counter-clockwise.

 

Let the saw run again at full

 

speed for about 10 seconds and note the difference of the enginesound. Repeat this procedure with the high speed needle H turned 1/4 turn more counter-clockwise. The saw has now been tested with the following settings: H=±0, H=+1/4, H=+1/2 from basic adjustment. At full speed the engine has produced a different sound for each setting. The high speed needle H is correctly set when the saw ”4-cycles” a little. If the saw ”whist- les” the setting is too lean. If there is too much exhaust gas at the same time as the saw ”4-cycles” much, the setting is too rich. Turn the high speed needle H until the setting sounds correct. NOTE! For optimum setting of the carburettor, contact a qualified servicing dealer who has a revolution counter at his disposal. The maximum speed recommended must not be exceeded.

Correctly adjusted carburettor

A correctly adjusted carburettor means that the saw accelerates without hesitation and the saw 4-cycles a little at max speed. Furthermore, the chain must not rotate at idling. A too lean adjusted low speed needle L may cause starting difficulties and bad acceleration.

A too lean adjusted high speed needle H gives lower power=less capacity, bad acceleration and/or damage to the engine.

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

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Contents 101 88 254XP/257/262XPSymbols in the operator’s manual KEY to SymbolsSymbols on the chain saw Contents Personal Protective Equipment Safety InstructionsChain SAW Safety Equipment Chain brake and front hand guard Right hand guard Throttle lockChain catcher Muffler Stop switchVibration damping system Checking the front hand guard Checking brake band wearChecking the automatic brake Checking the brake triggerThrottle lock 5 basic rules Cutting EquipmentBar Cutting equipment designed to minimise kickbackSaw chain Some terms that describe the bar and chainSharpening cutting teeth Sharpening your chain and adjusting raker clearanceGeneral information on sharpening cutting teeth Tensioning the chain General advice on setting raker clearanceSetting the raker clearance Chain oil Lubricating cutting equipmentFilling with chain oil Never use waste oilLubricating the clutch drum bearing Checking chain lubricationChecking wear on cutting equipment Lubricating the bar tip sprocketWhat is kickback? HOW to Avoid KickbackNever use the saw one- handed General rulesDo not let go of the handles 10 ft General Safety PrecautionsMin m General Working Instructions Basic safety rulesGeneral Basic cutting techniqueTerms CuttingSafe distance Tree felling techniqueLimbing Felling directionFelling Clearing the trunk and preparing your retreatFreeing a tree that has fallen badly = high accident risk General adviceCutting the trunk into logs Freeing a Trapped treeWhat is WHAT? Fitting a spike bumper AssemblyMounting guide bar and chain Fuelmix Fuel Handling10ft FuellingMin 3 m Start Start and StopCold engine Warm engineCarburettor MaintenanceStarter device Starter device assemblyChanging a broken or worn starter cord Tensioning the recoil springNeedle bearing maintenance Adjustment of the oil pumpAir filter Spark plugCooling system Centrifugal cleaning Air InjectionWinter use Heated handlesMonthly maintenance Weekly maintenance Daily maintenanceBar and chain combinations Technical Data254XP 257 Fuel and lubrication 262XP

254XP, 257, 262XP, 354XP, 257, 262XP specifications

Husqvarna is a well-respected name in the world of outdoor power equipment, especially when it comes to chainsaws. Among its lineup, the models 254XP, 257, 262XP, and 354XP stand out for their robust performance and innovative technologies, catering to both professional and amateur users.

The Husqvarna 254XP is known for its high power-to-weight ratio, making it a favorite among professionals who require portability without sacrificing performance. It features a 2.3 kW engine, providing ample power for a variety of cutting tasks. The chainsaw is equipped with a robust air injection system that removes larger debris before it reaches the air filter, helping to maintain engine performance and extend service intervals.

Similar to the 254XP, the Husqvarna 257 offers strong performance, but with enhancements tailored for even greater efficiency. It boasts an efficient combustion system, ensuring lower fuel consumption and reduced emissions, making it environmentally friendly. Another standout feature is the LowVib technology, which minimizes vibrations, making it easier for operators to work for extended periods without fatigue.

The Husqvarna 262XP takes a step further in terms of power and efficiency, featuring a 3.2 kW engine. This model is designed for heavy-duty tasks and is appreciated in the logging industry. Its advanced ignition system ensures quick starts and stable operation, even in challenging conditions. The X-Torq engine technology reduces fuel consumption and emissions, making it a green choice for professionals.

The 354XP is engineered for those who require a balance of power and weight. With a cutting capacity that satisfies both casual users and professionals, it delivers 2.9 kW of power. The chainsaw’s design incorporates features like the automatic chain lubrication system, ensuring optimal oil flow to the bar and chain, which prolongs their lifespan.

In terms of ergonomics, all these models come with comfort-grip handles and adjustable oil pumps, allowing for ease of use and control during operation. Their starting mechanisms are user-friendly, often featuring a decompression valve for easier pull starts.

These Husqvarna models exemplify the brand's commitment to merging power, efficiency, and user comfort. Whether tackling small projects or heavy-duty logging, the 254XP, 257, 262XP, and 354XP offer dependable solutions that meet the demands of today’s users.
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