Husqvarna 343R, 345RX, 343F, 345FX, 345FXT Workshop Manual
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Husqvarna 343R, 345RX, 343F, 345FX, 345FXT Workshop Manual

Husqvarna brush cutter workshop manual
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343R 345RX
343F 345FX 345FXT
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Summary of Contents for Husqvarna 343R, 345RX, 343F, 345FX, 345FXT

  • Page 1 Workshop manual 343R 345RX 343F 345FX 345FXT English...

  • Page 2: Table Of Contents

    Workshop Manual Brushcutter, Trimmer Model 343R, 345RX, 343F, 345FX, 345FXT Contents General recommendations ___________________ 2 1. Starter __________________________________ 3 2. Electrical system _________________________ 7 3. Fuel system _____________________________ 15 4. Centrifugal clutch ________________________ 31 5. Angle gear ______________________________ 37 6. Cylinder and piston ______________________ 41 7.

  • Page 3: General Recommendations

    General recommendations Remember: Special tools Never start the engine without the clutch and clutch drum Certain tasks in this handbook require the use of special mounted. tools. In sections where this is applicable, an image of the tool with an ordering number is provided. Do not grasp hot elements such as the muffler or the clutch before they have cooled sufficiently to avoid burn injuries.

  • Page 4: Starter

    Starter Contents Dismantling _________________________________ 4 Assembly __________________________________ 5 Replacing the drive dogs ______________________ 6...
  • Page 5 Starter WARNING! Protective glasses should be worn when working on the starter to avoid injury to the eyes if, for some reason, the return spring should fly out. Dismantling Dismantling Remove the starter from the engine. Remove the 4 bolts and lift off the starter.
  • Page 6 Starter Remove the spring cassette. Remove the two bolts holding the spring cassette and remove the cassette for replacement if necessary. WARNING! Wear protective glasses. The return spring can fly out and cause personal injury if improperly handled. Assembly Assembly Clean requisite parts and assemble in Clean all components before assembly: the reverse order as set out for disman-...
  • Page 7 Starter Tighten the return spring. Tighten the return spring. Check the spring tension. Lift up the starter cord when the return spring is completely loose and the cord pulled out completely. Then turn the starter pulley anti- clockwise 7 revolutions. Check the spring tension.

  • Page 8: Electrical System

    Electrical system Contents Checking the ignition spark ____________________ 8 Replacing the spark plug cover ________________ 10 Dismantling ________________________________ 11 Drive dogs _________________________________ 12 Assembly _________________________________ 12 Heated handles _____________________________ 12...

  • Page 9: Checking The Ignition Spark

    Electrical system The engine is equipped with an electronic ignition system completely without moving parts. Conse- quently, a faulty component cannot be repaired, but must be replaced by a new component. The spark in an electronic ignition system has a very short burn time and can therefore be interpreted as weak and can be difficult to see while troubleshooting.
  • Page 10 Electrical system If no spark occurs, disconnect the stop If no spark occurs even now, remove switch. the short-circuit cable from the connec- tion point in the carburettor compart- Replace the switch if necessary ment. If the plug now sparks, the fault is either in the stop switch or the short-circuit cable.

  • Page 11: Replacing The Spark Plug Cover

    Electrical system Still no spark? Still no spark? Check the air gap. Check the air gap between the flywheel magnet and the ignition module. The gap should be 0.3 mm. Use a 502 51 34-02 feeler gauge. 502 51 34-02 Adjust the air gap.

  • Page 12: Dismantling

    Electrical system Dismantling Dismantling Remove the starter, cylinder cover, and Remove the starter, cylinder cover, and spark plug. spark plug. Attach piston stop no. 502 54 15-01. Fit piston stop no. 502 54 15-01 in the spark plug hole. NOTE! Place the piston stop so it is caught between the piston and the cylinder head.

  • Page 13: Drive Dogs

    Electrical system Drive dogs Drive dogs Remove the bolts. The drive dogs can be easily replaced if they are damaged. Remove the hooks and the springs to replace them. Remove the bolts, the hooks and the springs. Mind the washer (A) so as not to lose it. Mind the washer (A) so as not to lose it.
  • Page 14 Electrical system Separate the contacts (A-A) and (B-B). Separate the contacts (A-A) and (B-B). Then extend the cables (A) and (B) with Then extend the cables (A) and (B) with approx. 90 cm long steel wires attached approx. 90 cm long steel wires attached to the contacts.
  • Page 15 Electrical system...

  • Page 16: Fuel System

    Fuel system Contents Air filter ___________________________________ 16 Tank venting _______________________________ 17 Fuel filter __________________________________ 17 Fuel pump _________________________________ 18 Carburettor ________________________________ 18 Assembly _________________________________ 24 Carburettor settings _________________________ 25 Throttle ___________________________________ 27...

  • Page 17: Air Filter

    Fuel system The carburettor can come from several different In addition to the fuel tank and carburettor, the fuel system manufacturers on our models, but the function and consists of the air filter, fuel filter and tank venting. repair methods are essentially the same. All these components interact so that the engine receives the optimal mixture of fuel and air to make it as efficient as possible.

  • Page 18: Tank Venting

    Fuel system Impregnate the filter with air filter oil. Impregnate the filter with air filter oil. Tip! Place the filter in a plastic bag and pour about a tablespoon of air filter oil no. 531 00 60-76 into the bag. Massage the oil into the air filter.

  • Page 19: Fuel Pump

    Fuel system Clean the filter externally if it is not too If the filter is not too dirty, its surface dirty. can be cleaned with a brush. Replace the filter if required. Otherwise it must be replaced. Check the fuel hose for cracks and leaks.
  • Page 20 Fuel system Remove the throttle cable and fuel hose Remove the throttle cable from the from the carburettor. carburettor’s lever arm using flat nose pliers. Remove the carburettor. Pull off the fuel hose and remove the carburettor. Tip! Open the fuel cap to avoid fuel spillage caused by any excess pressure.
  • Page 21 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).
  • Page 22 Fuel system In the event of leakage – remove the In the event of leakage – remove the needle valve. needle valve. Loosen the bolt and remove the lever arm, axle, needle valve and spring. Check the needle valve and the lever Check the needle valve for damage on arm for damage or wear.
  • Page 23 Fuel system Remove the movement limiters from the jet needles using flat nose pliers. Unscrew the jet needles. Do not lose the small washers (A)! Lift off the plastic and rubber guides. NOTE! Note how the jets are positioned. (For example, the H-needle is a little shorter than the L-needle).
  • Page 24 Fuel system Assembling the carburettor Assembling the carburettor Blow the carburettor housing clean. • Blow all channels in the carburettor compartment clean Fit a new plug. • Mount a new plug. Fit a new main jet. Use a suitable punch to get a completely tight seal.

  • Page 25: Assembly

    Fuel system Attach the various parts of the measur- Attach the various parts of the measur- ing unit in the reverse order as set out ing unit in the reverse order as set out for dismantling. for dismantling. The lever arm should lie flush with the carburettor housing.

  • Page 26: Carburettor Settings

    Fuel system Carburettor settings WARNING! When testing the engine in connection with carburettor adjustment, the clutch and clutch cover must be mounted together with the shaft and angle gear under all circumstances Otherwise there is a risk of the clutch becoming loose resulting in serious personal injury.
  • Page 27 Fuel system When checking the speed on a NOTE! trimmer no part of the cord A tachometer should always be used to find the optimal should be extended. setting. Use the 502 71 14-01 tachom- The recommended max. speed must not be exceeded. eter to check the speed.

  • Page 28: Throttle

    Fuel system Carburettor adjustment 345RX/FX Carburettor adjustment 345RX/FX Adjusting the L-needle Adjusting the H-needle 1. Mount the Trimmy Fix (4 wires) and use 3.3 mm smooth 1. Mount the Trimmy Fix (4 wires) and use 3.3 mm smooth cord. The cord length should be 160 mm measured from the cord.
  • Page 29 Fuel system Check for wear on pins (A) and (B). Replace the throttle control (C) and lever arm (D) if necessary. Check that the cables are properly pressed into the cut-outs (E) and that the throttle cable (F) is in the right groove.
  • Page 30 Fuel 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 necessary. The stop switch can also be disassem- bled now, and replaced if necessary.

  • Page 32: Centrifugal Clutch

    Centrifugal clutch Contents Dismantling ________________________________ 30 Assembly _________________________________ 32 Clutch drum _______________________________ 32...
  • Page 33 Centrifugal clutch The centrifugal clutch has the task of transferring the Some slipping occurs between the clutch and the clutch drum when accelerating as well as in the power from the engine to the cutting equipment’s drive axle. As the name implies, it works according to a reversed situation when the cutting equipment jams.
  • Page 34 Centrifugal clutch Dismantle the clutch from the crank- Replace the spark plug with piston stop shaft. no. 502 54 15-01. Move the engine body to the side so that the clutch becomes accessible. Unscrew the clutch from the crankshaft. 502 54 15-01 Fix the clutch in a vice and remove the Remove the 3 bolts and separate the 3 bolts.
  • Page 35 Centrifugal clutch Assembly Assembly Temporarily place the clutch shoes on Temporarily place the clutch shoes on the driving disc and loosely tighten the the driving disc and loosely tighten the bolts. bolts. Pry out the shoes and hook one spring NOTE! to each shoe from underneath.
  • Page 36 Centrifugal clutch Change the bearings in the clutch Change the bearings in the clutch housing if necessary. housing if necessary. Remove the circlip and push out the bearings with a suitable punch and hammer. Dismantling is easier if the clutch housing is heated to about 110°C.

  • Page 38: Angle Gear

    Angle gear Contents Dismantling ________________________________ 36 Assembly _________________________________ 37 Shaft _____________________________________ 38...
  • Page 39 Angle gear The angle gear has two purposes: Second, the angle gear contributes to the saw opera- tor’s working stance so that it is comfortable and at the The first is to gear down the engine’s high speed to same time efficient. The power from the engine, via the better suit the lower speed a saw blade or trimmer drive axle, shall in other words be angled so that the requires to work efficiently.
  • Page 40 Angle gear Remove the lubricant top-up plug. Remove the lubricant top-up plug and warm the entire gearbox using a hot air Warm the gearbox and knock it against gun to about 150°C. a wooden block so that the input axle falls out.
  • Page 41 Angle gear Shaft Shaft The shaft contains a drive axle guide The shaft contains a long plastic guide that is easily replaced. It can be to prevent vibrations in the drive axle. dismantled once the plastic sleeve (B) The guide (A) is easily removed for has been removed.

  • Page 42: Cylinder And Piston

    Cylinder and piston Contents Dismantling ________________________________ 42 Decompression valve ________________________ 43 Inlet manifold ______________________________ 44 Cleaning, inspection _________________________ 44 Assembly _________________________________ 44 Analysis and actions _________________________ 45 Service tips ________________________________ 49 Wear tolerances ____________________________ 50...

  • Page 43: Dismantling

    Cylinder and piston The cylinder and the piston are two of the compo- When servicing these components, cleanliness is of nents exposed to most strain in the engine. They must the utmost importance. It is therefore recommended withstand, for example, high speeds, large tempera- that the cylinder and the area around it be thoroughly ture swings and high pressure.

  • Page 44: Decompression Valve

    Cylinder and piston Dismantle the piston. Push the gudgeon pin from the piston using punch 502 52 42-01. If the pin is too tight, carefully warm the piston. 502 52 42-01 Decompression valve Decompression valve Dismantle the decompression valve. Remove the bolt (A) and the hose (B) that connect the decompression valve to the nipple on the cylinder.

  • Page 45: Inlet Manifold

    Cylinder and piston Inlet manifold Remove the air filter and carburettor. Remove the inlet manifold (A) from the partition (B). Check that it does not exhibit cracks or other damage that can cause leaks between the carburettor and cylinder. If necessary, fit a new inlet manifold in the reverse order as set out for dismantling.

  • Page 46: Analysis And Actions

    Cylinder and piston Place a new cylinder pedestal gasket Use a new gasket and fit the cylinder. on the cylinder. Make sure that the inlet manifold is correctly connected to the sleeve Lubricate the piston and the inlet manifold on the cylinder with a few coupling on the cylinder and that the impulse nipple sits right.
  • Page 47 For the best results we recommend Husqvarna two-stroke oil or ready-mixed fuel that is specially developed for air-cooled two-stroke engines. Mixing ratio: 1:50 (2%). If Husqvarna two-stroke oil is not available another good quality two-stroke oil can be used. Mixing ratio: 1:33 (3%) or 1:25 (4%).
  • Page 48 Cylinder and piston Piston damage caused by a too high engine speed. Typical damage associated with a too high engine speed includes broken piston rings, broken circlip on the gudgeon pin, faulty bearings or that the guide pin for the piston ring has become loose.
  • Page 49 Cylinder and piston Foreign objects Everything other than clean air and pure fuel that enters the engine’s inlet port causes some type of abnormal wear or damage to the cylinder and piston. This type of increased wear shows on the piston’s inlet side starting at the lower edge of the piston skirt.

  • Page 50: Service Tips

    Cylinder and piston Larger, harder particles that enter the engine cause serious damage to the under- side of the piston skirt. Cause: Action: • Air filter damaged or missing. Fit a new air filter. • Parts from the carburettor or intake Regular service and inspection.

  • Page 51: Wear Tolerances

    Cylinder and piston Wear tolerances Cylinder bore Piston ring gap Piston ring groove Piston ring play When the surface coating is Max. 1.0 mm with the piston Max. 1.6 mm. Clean the groove Max. 0.15 mm. Clean the groove worn and aluminium appears. ring inserted in the lower part before checking the measure- before checking the measure-...

  • Page 52: Crankshaft And Crankcase

    Crankshaft and crankcase Contents Dismantling ________________________________ 52 Inspecting the crankshaft _____________________ 54 Assembly _________________________________ 55 Leakage testing the crankcase _________________ 56...

  • Page 53: Dismantling

    Crankshaft and crankcase The crankshaft is journalled in the crankcase on The task of the crankshaft is to transform the reciprocating heavy-duty ball bearings. In addition to the journalling motion of the piston to rotation. This requires a stable point for the crankshaft, the crankcase acts as a design withstanding immense pressure and rotational and scavenging pump for the fuel/air mixture when this is bending strain, as well as high rotational speed.
  • Page 54 Crankshaft and crankcase Separate the crankcase halves. Fit tool 502 52 39-01 to the clutch side of the crankcase as illustrated. Separate the crankcase halves. 502 52 39-01 Fit tool 502 52 39-01 as illustrated. Push out the crankshaft from the Push out the crankshaft from the crankcase half.

  • Page 55: Inspecting The Crankshaft

    Crankshaft and crankcase Inspecting the Inspecting the crankshaft crankshaft Inspect the large end of the connecting The crankshaft cannot be reconditioned rod. but must be replaced if it is worn or damaged. Inspect the large end of the connecting rod. If seizure marks, discolouration on the sides or damaged needle holders are found the crankshaft must be replaced.

  • Page 56: Assembly

    Crankshaft and crankcase Check that the there is no play in the Check that the there is no play in the fill-out plates around the crank disks fill-out plates around the crank disks (applies to models F (applies to models F Assembly Assembly Mount the bearings in the crankcase...

  • Page 57: Leakage Testing The Crankcase

    Crankshaft and crankcase Fit the sealing rings. Lubricate the axle spindles with engine oil and press the sealing rings until level with the crankcase using a suitable punch or tool 502 50 30-19. The metal covers of the sealing rings should face outwards! 505 38 17-09 Assemble the remaining parts in the following order:...
  • Page 58 Hydrocarbon (HC) Nitrous oxide (NO Carbon monoxide (CO) Husqvarna E-Tech Carbon dioxide (CO Particles (PM) In 1996 Husqvarna presented a new, Air consisting of: improved two-stroke engine as a part 21% oxygen of the company’s efforts to produce 78% nitrogen...

  • Page 60: Tools

    Tools Contents Starter __________________________________ 60 Electrical system __________________________ 60 Fuel system _____________________________ 60 Centrifugal clutch _________________________ 60 Angle gear ______________________________ 61 Cylinder and piston ________________________ 61 Crankshaft and crankcase __________________ 61 Workshop equipment ______________________ 61...
  • Page 61 List of tools 531 00 48-63 502 50 18-01 502 51 91-01 531 00 60-76 502 21 58-01 502 71 13-01 502 50 83-01 531 03 03-98 502 54 15-01 502 51 34-02 501 60 02-03 502 52 16-02 502 50 06-01 502 50 18-01 502 11 46-03 502 54 15-01...
  • Page 62 List of tools 502 50 65-01 502 52 42-01 502 52 39-01 502 51 03-01 505 38 17-09 503 97 64-01 502 50 70-01 531 03 06-23 503 80 17-01 502 50 18-01 502 50 30-19 502 71 14-01 502 54 11-02 505 69 85-70 503 84 40-01 503 55 22-01...
  • Page 63 114 01 98-26 2003W24...

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