Husqvarna 55 EPA I manual Maintenance, General, Carburetor adjustment

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MAINTENANCE

General

The user must only carry out the maintenance and service work described in this manual. More extensive work must be carried out by an authorised service workshop.

Carburetor adjustment

Due to existing environmental and emissions legislation your chain saw is equipped with movement limiters on the carburetor adjuster screws. These limit the adjustment possibilities to a maximum of a 1/2 turn.

1/2

1/2

Your Husqvarna product has been designed and manufactured to specifications that reduce harmful emissions.

Function

•The carburetor governs the engine’s speed via the throttle control. Air and fuel are mixed in the carburetor. The air/ fuel mixture is adjustable. Correct adjustment is essential to get the best performance from the machine.

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

•The carburetor has three adjustment controls:

-L = Low speed jet

-H = High speed jet

-T = Idle adjustment screw

•The L and H-jets are used to adjust the supply of fuel to match the rate that air is admitted, which is controlled with the throttle. 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 lean mixture gives a higher engine speed and a rich mixture gives a lower engine speed.

•The T-screw regulates the throttle setting at idle speed. If the T-screw is turned clockwise this gives a higher idle speed; turning it anti-clockwise gives a lower idle speed.

Basic settings and running in

The basic carburetor settings are adjusted during testing at the factory. Avoid running at a too high speed for extended periods during the first 10 hours.

CAUTION! If the chain rotates while idling the T-screw must be turned anti-clockwise until the chain stops.

Rec. idle speed: 2500 rpm

Fine adjustment

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

Conditions

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

•Do not attempt to adjust the L and H jets beyond either stop as this could cause damage.

•Now start the machine according to the starting instructions and let it warm up for 10 minutes. CAUTION!

If the chain rotates while idling the T-screw must be turned anti-clockwise until the chain stops.

•Place the machine 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 jet L

Turn the low speed jet L clockwise until it stops. If the engine accelerates poorly or idles unevenly, turn the low speed jet L anticlockwise until good acceleration and idling are achieved.

Fine adjustment of the idling speed T

Adjust the idle speed with the T-screw. If it is necessary to re- adjust, turn the T-screw clockwise while the engine is running, 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.

WARNING! Contact your servicing dealer, if

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

High speed jet H

At the factory the engine is adjusted at sea level. When working at a high altitude or in different weather conditions, temperatures and atmospheric humidity, it may be necessary to make minor adjustments to the high speed jet.

CAUTION! If the high speed jet is screwed in too far, it may damage the piston/cylinder.

When test run at the factory, the high speed jet is set so that the engine satisfies the applicable legal requirements at the same time as achieving maximum performance. The carburetor’s high speed jet is then locked using a limiter cap in the fully screwed out position. The limiter cap limits the potential to adjust the high speed jet to at most half a turn.

To adjust the carburetor correctly you should contact a mechanic with access to a rev counter.

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Contents Operator’s manual 55 EPA Symbols in the operator’s manual KEY to SymbolsSymbols on the machine Contents Dear customer IntroductionWhat is what on the chain saw? What is WHAT?Always use common sense General Safety PrecautionsBefore using a new chain saw Chain brake and front hand guard Machine′s safety equipmentPersonal protective equipment General Safety Precautions Right hand guard Throttle lockChain catcher Cutting equipment Stop switchVibration damping system MufflerCutting equipment designed to reduce kickback General rulesBar ChainSharpening cutting teeth Sharpening your chain and adjusting depth gauge settingGeneral information on sharpening cutting teeth Tensioning the chain General advice on adjusting depth gauge settingAdjustment of depth gauge setting Chain oil Lubricating cutting equipmentFilling with chain oil Checking chain lubricationChecking wear on cutting equipment Chain drive sprocketNeedle bearing lubrication Fitting the bar and chain AssemblyFuel Fuel HandlingFueling Fuel safetyTransport and storage Long-term storageStarting and stopping Starting and StoppingCold engine Warm engineStopping Working Techniques Basic safety rulesBefore use General working instructionsGeneral rules Terms Basic cutting techniqueGeneral Cutting LimbingSafe distance Tree felling techniqueFelling direction Clearing the trunk and preparing your retreatDirectional cuts FellingFreeing a tree that has fallen badly General adviceFreeing a trapped tree Cutting trees and branches that are in tensionCutting the trunk into logs How to avoid kickbackWhat is kickback? General MaintenanceCarburetor adjustment Checking brake band wear Correctly adjusted carburetorChecking the front hand guard Checking the inertia brake releaseThrottle lock Changing a broken or worn starter cord MufflerStarter Tensioning the recoil spring Air filterChanging a broken recoil spring Fitting the starterLubricating the bar tip sprocket Spark plugNeedle bearing lubrication Cooling systemWinter use Temperature 0C 32F or colderDaily maintenance Weekly maintenance Monthly maintenance Maintenance scheduleTechnical data Technical DataBar and chain combinations Saw chain filing and file gauges Your Warranty Rights and Obligations Federal Emission Control Warranty StatementSafety precautions for chain saw users American Standard Safety PrecautionsKickback safety precautions Other safety precautions´z+R7y¶5m¨ Page 1150238-95 ´z+R7y¶5m¨ ´z+R7y¶5m¨
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