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Husqvarna 343R, 345RX, 343F, 345FX, 345FXT manual The pump unit, Dismantling the carburettor

Models: 343R, 345RX, 343F, 345FX, 345FXT

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The pump unit

3	Fuel system
	The pump unit	The pump unit
	Pumps fuel from the tank to the carbu-	This is where the pump diaphragm (E)
	rettor.	that pumps fuel from the tank to the
		carburettor’s measuring unit is found.
		The diaphragm is affected by pressure
		variations in the engine’s crankcase via
		an impulse channel (F).
		If the channel is blocked, by grease or a
		wrongly facing gasket, for example, the
		pump unit does not function and the
		engine cannot be started.
	Dismantling the carburettor	Dismantling the carburettor
	Remove the control diaphragm and	Carefully remove the control dia-
	check for damage.	phragm (A) and gasket (B).
	Replace if required.	Check the diaphragm for holes and
		wear on the pin (C).
		Replace the diaphragm if required.

Pressure test the metering unit.	Connect pressure tester 531 03 06-23
	to the fuel hose nipple.

Lower the carburettor in a vessel with petrol in order to discover any leaks more easily.

Test the pressure at 50 kPa. No leakage is permitted.

531 03 06-23

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Husqvarna 343R, 345RX, 343F, 345FX, 345FXT manual The pump unit, Dismantling the carburettor, Fuel system

Contents

English 343R 345RX 343F 345FX 345FXTWorkshop manual General recommendations ___________________ Model 343R, 345RX, 343F, 345FX, 345FXT Contents1.Starter __________________________________ 2.Electrical system _________________________Remember General recommendationsSpecial tools Fire risk1 Starter Contents1Starter DismantlingDismantling Assembly StarterAssembly Replacing the drive dogs 1StarterReplacing the drive dogs Contents Electrical systemAssembly _________________________________ Checking the ignition spark ____________________Checking the ignition spark Electrical system502 71 Checking the ignition sparkElectrical system plug cover Replacing the spark502 50 Electrical systemElectrical system 502 54Dismantling DismantlingHeated handles Drive dogsDo not pry off the heating element before the locking catch has beenElectrical system Wiring diagramElectrical system Contents Fuel systemAssembly _________________________________ Carburettor settings _________________________Fuel system Air filterAir filter Fuel filter Tank ventingMassage the oil into the air filter Fuel systemCarburettor Fuel pumpDismantling Fuel systemThe metering unit The carburettor’s designThe blending unit Fuel systemDismantling the carburettor The pump unitFuel system The pump unitIn the event of leakage – remove the needle valve Fuel systempositioned Note how the jets areFor example, the H-needleis a little shorter than the L-needleUse Loctite on the valve screws Assembling the carburettorFuel system Assembling the carburettorThe H-needleis a little shorter are not bent or pinched when thethan the L-needle Check carefully that the fuel hosesBasic setting Carburettor settingsFine adjustment FunctionCorrectly adjusted carburettor settingThe recommended max. speed must not be exceeded Idling speed T-screwadjustment 345RX/FX Carburettor adjustment 345RX/FXAdjusting the L-needle Adjusting the HFuel system Check for wear on pins A and BFuel system Disassemble the throttle control A, the lock to prevent accidental throttle operation B, the start throttle lock C and the throttle stop D in order to check if replacement is necessaryPage Contents 4 Centrifugal clutchAssembly _________________________________ Dismantling ________________________________502 21 Centrifugal clutchDismantling Dismantling502 54 Centrifugal clutch502 11 Clutch drumAssembly AssemblyCentrifugal clutch Change the bearings in the clutch housing if necessaryPage Contents 5 Angle gearAssembly _________________________________ Dismantling ________________________________Let the small circlip around the axle remain Angle gearDismantling Dismantling503 97 AssemblyAngle gear 503 80 ShaftAngle gear ShaftContents 6 Cylinder and pistonCleaning, inspection _________________________ Assembly _________________________________Dismantling Cylinder and pistonDecompression valve Turn the valve the right way when fittingCylinder and piston Decompression valvemanifold is fitted using a Cleaning, inspectionInlet manifold Exercise caution if the inletInsufficient lubrication Analysis and actionsCause ActionCylinder and piston Piston scoring caused by heavy carbon depositsCause ActionPiston ring breakage Piston damage caused by a too high engine speedPiston ring guide pin Damage caused byCylinder and piston Foreign objectsCause ActionDefect Service tipsBe careful with the lower edge of the piston ring groove. If this is damaged, or if carbon depositsCylinder bore Wear tolerancesPiston ring gap Piston ring grooveContents 7 Crankshaft and crankcaseAssembly _________________________________ Leakage testing the crankcase _________________Crankshaft and crankcase DismantlingDismantling 502 52 Crankshaft and crankcasecrankshaft Inspecting theCrankshaft and crankcase Inspecting theAssembly AssemblyCrankshaft and crankcase 502 50crankcase Leakage testing thePress down the sealing plates as far as possible between the boltsHusqvarna E-Tech 503 55Crankshaft and crankcase Page Contents ToolsStarter __________________________________ Electrical system __________________________505 38 List of toolsStarter Electricalgear List of toolsCrankshaft Workshop2003W24 114 01