Husqvarna 343F, 345FX, 345FXT, 343R, 345RX manual Husqvarna E-Tech, 503 55

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Crankshaft and crankcase

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Fit plug 503 55 22-01 instead of the decompression valve.

Connect meter 531 03 06-23 and check for leakage.

531 03 06-23

503 55 22-01

Fit plug 503 55 22-01 instead of the decompression valve.

Connect meter 531 03 06-23 to the nipple and pump up a pressure of 50 kPa (0.5 kp/cm2) in the crankcase.

Max. permitted leakage:

20 kPa (0.2 kp/cm2) per 30 seconds.

Connect meter 531 03 06-23 to the nipple and lower the pressure in the crankcase to 50 kPa (0.5 kp/cm2).

Max. permitted leakage:

20 kPa (0.2 kp/cm2) per 30 seconds.

Any leakage can be difficult to localise if the crankcase is depressurised.

When leakage has been established with a vacuum, you can apply a slight overpressure (0.1–0.3 kp/cm2) and at the same time apply a layer of thin oil to the joints and the sealing ring contact surfaces on the crankcase to make leak detection easier. Bubbles clearly mark

Fuel consisting of

Hydrocarbons (petrol)

Two-stroke oil (2%)

Air consisting of: 21% oxygen

78% nitrogen

1% other

Fuel/air mixture consisting of:

92% air

8% petrol

Exhaust gases consisting of Hydrocarbon (HC) Nitrous oxide (NOx) Carbon monoxide (CO) Carbon dioxide (CO2) Particles (PM)

the position of the leakage.

Husqvarna E-Tech

In 1996 Husqvarna presented a new, improved two-stroke engine as a part of the company’s efforts to produce engines that emit smaller amounts of hazardous substances.

The new engine was given the desig- nation E-Tech and was first used in a new brush cutter model.

More stringent environment regulations in the USA, which primarily involve a lowering of the hydrocarbons, nitrous oxides and carbon monoxide content, brought about the new engine design.

Environment degradation is reduced through decreasing the amount of unburned gases (flushing losses) in the exhaust fumes.

Comparisons between an E-Tech engine and an older engine design show that the CO content has been halved and the hydrocarbons and nitrous oxide contents have been reduced by close to 70%. In addition a powerful increase in output is gained.

What makes the E-Tech engine design unique is not a specific design solution but rather several solutions interacting to reduce flushing losses in the engine.

Adjustable fuel jets with movement limiters

The carburettor’s job is to mix the air and fuel in the right proportions to give a combustible mixture, irrespective of the speed and workload. The carburet- tor’s adjustable needles have been fitted with movement limiters to prevent the engine from being run with a too “rich” fuel/air mixture. (Also see the “Fuel system” chapter).

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Contents English Model 343R, 345RX, 343F, 345FX, 345FXT Contents Workshop Manual Brushcutter, TrimmerGeneral recommendations Contents Starter1Starter DismantlingAssembly StarterReplacing the drive dogs Electrical system Checking the ignition spark Electrical system502 71 Tip Replacing the spark Plug cover 502 50502 54 Drive dogs Heated handlesWiring diagram Electrical system Fuel system Fuel system Air filterTank venting Fuel filterCarburettor Fuel pumpDismantling Metering unit Carburettor’s designBlending unit Pump unit Dismantling the carburettorFuel system For example, the H-needle is a PositionedLittle shorter than the L-needle Assembling the carburettor Check carefully that the fuel hoses H-needle is a little shorterThan the L-needle Are not bent or pinched whenBasic setting Carburettor settingsFine adjustment Tachometer should always be used to find the optimal Setting Recommended max. speed must not be exceededCorrectly adjusted carburettor Idling speed T-screwThrottle Carburettor adjustment 345RX/FXAdjusting the L-needle Adjusting the H-needle 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 When the valve is fitted the small hole must face outwards Turn the valve the right way when fittingDecompression valve Cleaning, inspection Inlet manifoldInsufficient lubrication Analysis and actionsCause Action 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 Far as possible between the bolts Leakage testing CrankcasePress down the sealing plates as To ensure a proper sealHusqvarna E-Tech 503 55
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