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

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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	0Carefully 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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Contents English Workshop Manual Brushcutter, Trimmer Model 343R, 345RX, 343F, 345FX, 345FXT ContentsGeneral recommendations Starter ContentsDismantling 1StarterStarter AssemblyReplacing the drive dogs Electrical system Electrical system Checking the ignition spark502 71 Tip 502 50 Replacing the spark Plug cover502 54 Heated handles Drive dogsWiring diagram Electrical system Fuel system Air filter Fuel systemFuel filter Tank ventingFuel pump CarburettorDismantling Carburettor’s design Metering unitBlending unit Dismantling the carburettor Pump unitFuel system Positioned For example, the H-needle is aLittle shorter than the L-needle Assembling the carburettor Than the L-needle H-needle is a little shorterCheck carefully that the fuel hoses Are not bent or pinched whenCarburettor settings Basic settingFine adjustment Correctly adjusted carburettor Setting Recommended max. speed must not be exceededTachometer should always be used to find the optimal Idling speed T-screwAdjusting the L-needle Adjusting the H-needle Carburettor adjustment 345RX/FXThrottle RotatingCheck for wear on pins a and B Tip Page Centrifugal clutch 502 21 Centrifugal clutchDo not lose the sleeve bearings found in the clutch shoes Centrifugal clutch502 11 Clutch drumChange the bearings in the clutch housing if necessary Page Angle gear Let the small circlip around the axle remain Angle gearInput axle with pinion must be dismantled first 503 97503 80 ShaftCylinder and piston Cylinder and piston Turn the valve the right way when fitting When the valve is fitted the small hole must face outwardsDecompression valve Inlet manifold Cleaning, inspectionAnalysis and actions Insufficient lubricationCause Action Piston scoring caused by heavy carbon deposits Piston ring breakage Piston damage caused by a too high engine speedCause Foreign objectsDefect Action Service tipsWear tolerances Crankshaft and crankcase Crankshaft and crankcase 502 52 Crankshaft and crankcaseInspecting Crankshaft Assembly Press down the sealing plates as Leakage testing CrankcaseFar as possible between the bolts To ensure a proper seal503 55 Husqvarna E-Tech