Husqvarna 346XP 351 manual Maintenance, Carburettor

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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.

•The satisfactory operation of a catalytic converter depends, among other factors, on the correct adjustment of the carburettor. Follow carefully the instructions below, using a tachometer to check engine speed.

•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.

LH

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

H = High speed jet.

T = Adjustment screw for idling.

T

•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.

WARNING! The catalytic converter muffler gets very hot during and after use. This also applies during idling. Be aware of the fire hazard, especially when handling the saw near flammable substances or vapours.

Basic setting and running in

The carburettor is adjusted to a basic setting when the saw is tested at the factory. The basic setting is: H = 1 turn respective L = 1 turn.

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 speed 6-700 rpm under the recommended max. speed.

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

The recommended speed 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. speed

Idling speed

346XP:

14 200 rpm

2 700 rpm

351:

12 500 rpm

2 700 rpm

Changing the type of fuel

Fine tuning may be required if the chain saw, after changing the type of fuel, performs differently with regard to starting, acceleration, max. speed, etc.

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

L

 

 

 

 

 

 

 

 

 

turn counter-clockwise.

 

 

 

 

 

 

 

 

 

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,

H

turn the 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 accelera- tion. 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 English 346XPSymbols KEY to SymbolsContents Personal Protective Equipment Safety Instructions3a Starting Chain brake and front hand guardRight hand guard Throttle lockChain catcher Muffler Stop switchVibration damping system Checking the front hand guard Checking brake band wearChecking the inertia brake release 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 Filling with chain oil Lubricating cutting equipmentChain oil Checking chain lubrication Needle bearing maintenanceChecking wear on cutting equipment Lubricating the bar tip sprocketWhat is kickback? HOW to Avoid KickbackDo not let go of the handles General rulesGeneral Safety Precautions 10 ft Basic safety rulesMin m General Basic cutting techniqueTerms CuttingSafe distance Tree felling techniqueLimbing Felling directionFelling Clearing the trunk and preparing your retreatCutting the trunk into logs Freeing a tree that has fallen badly = high accident riskFreeing a Trapped tree Cutting trees and branches that are in tension PreparationsWhat is what? What is WHAT?Fitting a spike bumper AssemblyMounting guide bar and chain Fuelmix Fuel HandlingChain oil FuellingMin 3 m 10ftStart and stop Start and StopStart StopCarburettor MaintenanceStarter device Starter device assemblyChanging a broken or worn starter cord Tensioning the recoil springMuffler Needle bearing maintenance Spark plugAir filter Centrifugal cleaning Air Injection Adjustment of the oil pump Heated handles 346XPG, 351GCooling system Winter useMonthly maintenance Weekly maintenance Daily maintenance346XP 351 Technical DataBar Chain Bar and chain combinations2001W49 114 00

346XP 351 specifications

The Husqvarna 346XP and 351 chainsaws are celebrated models within the Husqvarna lineup, recognized for their excellence in performance, efficiency, and ease of use. Designed predominantly for professional use, these chainsaws incorporate advanced technology and ergonomic features that cater to the needs of tree care specialists, landscapers, and serious woodworkers.

One of the standout features of the Husqvarna 346XP is its lightweight design, which allows for easy maneuverability and reduced fatigue during extended use. Weighing around 10.8 pounds, the chainsaw is equipped with a powerful 50.1cc, 2.8 horsepower engine, delivering exceptional cutting performance while maintaining efficient fuel consumption. The model comes equipped with a 15 to 18-inch guide bar, providing versatility for various cutting tasks, from limbing to felling small trees.

The 351 model offers similar performance metrics but is designed slightly differently, featuring an improved air injection system for cleaner operation. This system actively collects debris before it reaches the air filter, extending the service intervals and enhancing engine life. The powerful 51.7cc engine on the 351 provides a higher power output compared to the 346XP, suited for even the most demanding cutting jobs.

Both chainsaws utilize Husqvarna’s X-Torq engine technology, which reduces fuel consumption by up to 20% while lowering emissions. This not only promotes environmental sustainability but also translates into cost savings for users. The LowVib technology integrated into both models minimizes vibrations, ensuring a more comfortable experience and reducing operator fatigue.

Enhanced safety features are also paramount in both chainsaws. The inertia-activated chain brake activates quickly in the event of a kickback, providing an additional layer of protection. An adjustable oil pump allows users to control the lubrication rate, optimizing the chainsaw's performance based on the type of work being performed.

The ergonomic design of the handles enhances grip and control, allowing for precision cutting. These chainsaws are user-friendly, catering to both experienced operators and those new to chainsaw work. Overall, the Husqvarna 346XP and 351 represent a perfect blend of power, technology, and comfort, making them reliable choices for professional and serious amateur users alike.
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