Manuals / Husqvarna / Lawn and Garden / Chainsaw

Husqvarna 1018855-26 Carburettor, Description, Design, The liquid and its vapours are poisonous

Models: 1018855-26 965030296 965030298

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CARBURETTOR

Description

The diagrams in this description do not correspond with the carburettor fitted on the chain saws. They serve only to show the principles of design and operation.

Design

The carburettor consists of three sub-systems:

•Metering unit, A.

•Mixing venturi, B.

•Pump unit, C.

The metering unit (A) contains the jets and fuel control functions. It is here the correct amount of fuel for the given engine speed and power is metered.

The mixing venturi (B) houses the choke, throttle valve and diffuser jets. Here air is mixed with the fuel to give a fuel/air mixture that can be ignited by the ignition spark.

In the pump unit (C), fuel is pumped from the fuel tank to the metering unit. One side of the pump diaphragm is connected to the crankcase and pulses in time with the pressure changes in the crankcase. The other side of the diaphragm pumps the fuel.

!WARNING!

The fuel used in the chain saw poses the following hazards:

1.The liquid and its vapours are poisonous.

2.Can cause skin irritation.

3.Is highly inflammable.

A

B

C

English – 83

Image 83

Husqvarna 1018855-26 manual Carburettor, Description, Design, The fuel used in the chain saw poses the following hazards

Contents

101 Husqvarna Chain SawsWorkshop Manual Anti-vibration system LIST OF CONTENTSAir filter Tank unitGeneral SafetyUpdates INTRODUCTIONINTRODUCTION Repair of a specific sub-assemblyDismantling and reassembly of the entire chain saw Special instructions SAFETY REGULATIONSGeneral Instructions 6 - English TECHNICAL DATATECHNICAL DATA 8 - English TECHNICAL DATATECHNICAL DATA 10 - English TECHNICAL DATATECHNICAL DATA 12 - English TECHNICAL DATATECHNICAL DATA 502 50 18-01 4 mm 502 50 19-01 3 mm 502 50 88-01 5 mm TOOLSTools for all chain saws 502 50 57-01 3/16 502 50 16-01 6 mm 502 50 64-01 5 mmcompl 502 50 Tools for saws 36 andTools for saws 40, 45, 51 and TOOLScompl 502 51 Tools for saws 42, 242 andTools for saws 254, 257 and TOOLScompl 502 51 Tools for saws 61, 268 andTools for saws 281 and TOOLScompl 502 51 Tools for saws 394 andTOOLS 3 mm 4 mm 5 mm 3/16 8 mm 10 mm 502 50Designation List of toolsTOOLS Order numberCharacter key SERVICE DATA Saws 36 andEnglish SERVICE DATA22 - English SERVICE DATA Saws 42, 242 andCharacter key English SERVICE DATA24 - English Saws 40 andSERVICE DATA Character keyEnglish SERVICE DATA26 - English Saws 51 andSERVICE DATA Character key3-4English SERVICE DATA28 - English SERVICE DATA Saws 254 and5254 Character keyEnglish SERVICE DATA30 - English SERVICE DATACharacter key English SERVICE DATA32 - English SERVICE DATA Saws 61, 268 andCharacter key English SERVICE DATA34 - English SERVICE DATA Saws 281 andCharacter key English SERVICE DATA36 - English SERVICE DATACharacter key 3-5 5-6 SERVICE DATA20-22,5 10-12 12-14 30-40 2-338 - English SERVICE DATA SawCharacter key English SERVICE DATAIdling low rpm cont TROUBLE SHOOTING Trouble shooting schematicStarting Idling low rpmAcceleration and retardation TROUBLE SHOOTINGTrouble shooting methods High rpmWear protective glasses SAFETY EQUIPMENTChain brake DismantlingSAFETY EQUIPMENT 44 - English Cleaning and InspectionAssembly SAFETY EQUIPMENTSAFETY EQUIPMENT 46 - English SAFETY EQUIPMENTThe engine should not be running during the test Checking brake operationSAFETY EQUIPMENT Replacing SAFETY EQUIPMENT Chain catcherDescription Do not touch the muffler until it has cooled. Risk of burns MufflerSAFETY EQUIPMENT Dismantlingwhen working on a catalytic converterWARNING SAFETY EQUIPMENTCleaning and Inspection AssemblyDismantling SAFETY EQUIPMENT Stop switchCleaning and Inspection AssemblyThe fuel used in the chain saw poses the following hazards Throttle lockSAFETY EQUIPMENT DismantlingSAFETY EQUIPMENT Check that the springs, where fitted, are Cleaning and inspectionSAFETY EQUIPMENT Clean all parts1. The liquid and its vapours are poisonous SAFETY EQUIPMENTAssembly The fuel used in the chain saw poses the following hazards56 - English SAFETY EQUIPMENTWear protective glasses STARTERDismantling Remove the parts of the old ferrule Changing the ferruleCleaning and Inspection STARTERSTARTER Assembly60 - English STARTERCheck the cord tension Dismantling ELECTRICAL SYSTEM Ignition systemELECTRICAL SYSTEM ELECTRICAL SYSTEM Cleaning and InspectionAssembly Clean all parts, especially the flywheel and shaft taper64 - English Stop switchFitting the spark plug cover ELECTRICAL SYSTEMDescription Trouble shootingHandle heating ELECTRICAL SYSTEMChecking the heat loops in the rear handles Checking the power switchELECTRICAL SYSTEM Checking the generatorDismantling CENTRIFUGAL CLUTCHCENTRIFUGAL CLUTCH Cleaning and InspectionClean all parts and inspect the following NOTE! The bearing can also be greased later through the hole on the crankshaft AssemblyCENTRIFUGAL CLUTCH 70 - English LUBRICATION SYSTEMDismantling LUBRICATION SYSTEM 72 - English LUBRICATION SYSTEM36/41 40/4551/55 LUBRICATION SYSTEM74 - English LUBRICATION SYSTEM40/45 Turn the screw until the worm gear is removed Dismantling the oil pumps worm gearLUBRICATION SYSTEM First screw the tool onto the entire worm gearLUBRICATION SYSTEM Cleaning and InspectionThat the taper on the adjuster screw shows no signs of wear LUBRICATION SYSTEM Assembling the worm gearAssembling the oil pump 78 - English LUBRICATION SYSTEMLUBRICATION SYSTEM Saws 42, 61, 242, 246, 254, 257, 262, 268, 272, 281, 288, 394 and LUBRICATION SYSTEM40/45 36/4150/51 LUBRICATION SYSTEM82 - English LUBRICATION SYSTEM40/45 51/55The fuel used in the chain saw poses the following hazards CARBURETTORDescription DesignOperation CARBURETTOR1. The liquid and its vapours are poisonous CARBURETTORDismantling The fuel used in the chain saw poses the following hazards86 - English Tillotson HS 228 BTillotson HS 255 B CARBURETTORCARBURETTOR Tillotson HS 260 AWalbro HDA and HD 88 - English Walbro WJWalbro WG CARBURETTORCARBURETTOR Walbro WTZAMA C1Q-EL1 1. The liquid and its vapours are poisonous Cleaning and InspectionCARBURETTOR The fuel used in the chain saw poses the following hazardsThe fuel used in the chain saw poses the following hazards AssemblyCARBURETTOR Plugs92 - English CARBURETTORTillotson HS 228 B Tillotson HS 255 B CARBURETTOR94 - English CARBURETTORTillotson HS 260 A CARBURETTOR Walbro HDA och HD96 - English CARBURETTORWalbro WJ Walbro WG CARBURETTOR98 - English CARBURETTORWalbro WT ZAMA C1Q-EL1 CARBURETTORThe fuel used in the chain saw poses the following hazards Pressure testingRefitting onto chain saw CARBURETTORCompressed air at a high pressure can damage the foam AIR FILTER268K, 272K and 272S Prefilter102 - English AIR FILTERMain filter The fuel used in the chain saw poses the following hazards TANK UNITCleaning and Inspection Dismantling268K Bolts placed atTANK UNIT 262XPEnsure that the fuel pipe and throttle cable are not damaged AssemblyTANK UNIT 106 - English ANTI-VIBRATION SYSTEMDescription DismantlingANTI-VIBRATION SYSTEM Assembly108 - English PISTON AND CYLINDERDismantling 1. The piston crown 2. The top of the cylinder bore Cleaning and InspectionPISTON AND CYLINDER PISTON AND CYLINDER Faults and causesPISTON AND CYLINDER Assembly112 - English PISTON AND CYLINDERCrankcase and cylinder Pressure testingPISTON AND CYLINDER Decompression valveEnsure that no dirt or foreign particles enter the bearings CRANKCASE AND CRANKSHAFTDismantling CRANKCASE AND CRANKSHAFT 116 - English Cleaning and InspectionCRANKCASE AND CRANKSHAFT Ensure that dirt and foreign particles do not enter the bearing AssemblyCRANKCASE AND CRANKSHAFT 118 - English CRANKCASE AND CRANKSHAFTEnsure excess gasket material does not fall into the crankcase CRANKCASE AND CRANKSHAFT120 - English CRANKCASE AND CRANKSHAFTEnsure that dirt and foreign particles do not enter the bearing CRANKCASE AND CRANKSHAFT Bar boltsDismantling Changing the sealsCRANKCASE AND CRANKSHAFT CRANKCASE AND CRANKSHAFT Assembly3120 CRANKCASE AND CRANKSHAFT3.5 mm 42, 242, 246 1 mm