Husqvarna 343F, 345FX, 345FXT, 343R, 345RX manual Decompression valve

Page 44

Cylinder and piston

6

Dismantle the piston.

502 52 42-01

Decompression valve

Dismantle the decompression valve.

Check that the non-return valve (A) is tight under a vacuum of – 50 kPa.

Otherwise replace the valve.

NOTE!

Turn the valve the right way when fitting.

531 03 06-23

Clean the decompression valve and check that the valve head is not dam- aged (burnt) and that the valve oper- ates easily.

If necessary, grind the valve with fine- grained valve grinding compound.

Push the gudgeon pin from the piston using punch 502 52 42-01.

If the pin is too tight, carefully warm the piston.

Decompression valve

Remove the bolt (A) and the hose (B) that connect the decompression valve to the nipple on the cylinder.

Unscrew the valve from the cylinder.

Inside the rubber sleeve on the nipple in the cylinder is a non-return valve (A).

Check with pressure gauge 531 03 06-23.

Pump up a vacuum of – 50 kPa. The valve must be fully tight. Otherwise replace the valve.

NOTE!

When the valve is fitted the small hole must face outwards.

Clean the decompression valve with white spirit or thinner and blow dry with compressed air.

Check that the valve moves easily in the guide and that the valve head is not damaged (burnt).

If necessary, grind the valve into the seat using fine-grained valve grinding compound.

Tip!

Use washer no. 502 54 11-01 as a friction lining against the valve head when grinding.

Fit the decompression valve in the cylinder.

43

Image 44

Contents English Model 343R, 345RX, 343F, 345FX, 345FXT Contents Workshop Manual Brushcutter, TrimmerGeneral recommendations Contents Starter1Starter DismantlingAssembly StarterReplacing the drive dogs Electrical system 502 71 Electrical systemChecking the ignition spark Tip Replacing the spark Plug cover 502 50502 54 Drive dogs Heated handlesWiring diagram Electrical system Fuel system Fuel system Air filterTank venting Fuel filterDismantling Fuel pumpCarburettor Blending unit Carburettor’s designMetering unit Pump unit Dismantling the carburettorFuel system Little shorter than the L-needle PositionedFor example, the H-needle is a Assembling the carburettor H-needle is a little shorter Than the L-needleCheck carefully that the fuel hoses Are not bent or pinched whenFine adjustment Carburettor settingsBasic setting Setting Recommended max. speed must not be exceeded Correctly adjusted carburettorTachometer should always be used to find the optimal Idling speed T-screwCarburettor adjustment 345RX/FX Adjusting the L-needle Adjusting the H-needleThrottle RotatingCheck for wear on pins a and B Tip Page Centrifugal clutch Centrifugal clutch 502 21Centrifugal clutch Do not lose the sleeve bearings found in the clutch shoesClutch drum 502 11Change the bearings in the clutch housing if necessary Page Angle gear Angle gear Let the small circlip around the axle remain503 97 Input axle with pinion must be dismantled firstShaft 503 80Cylinder and piston Cylinder and piston Decompression valve Turn the valve the right way when fittingWhen the valve is fitted the small hole must face outwards Cleaning, inspection Inlet manifoldCause Action Analysis and actionsInsufficient lubrication Piston scoring caused by heavy carbon deposits Piston damage caused by a too high engine speed Piston ring breakageForeign objects CauseService tips Defect ActionWear tolerances Crankshaft and crankcase Crankshaft and crankcase Crankshaft and crankcase 502 52Inspecting Crankshaft Assembly Leakage testing Crankcase Press down the sealing plates asFar as possible between the bolts To ensure a proper sealHusqvarna E-Tech 503 55