Service data ............14 Safety equipment ..........18 Repair instructions ..........22 Troubleshooting ........... 58 Husqvarna AB has a policy of continuous product development and therefore reserves the right to modify the design and appearance of products without prior notice. English -...
Index Index Angle gear 53 Muffler 19 Disassemble the angle gear 53 Assembling the muffler 19 Assemble the angle gear 54 Dismantling the muffler 19 Carburettor 35 Service data 14 Adjustment 42 Service tools 12 Assembly 38 Starter 23 Cleaning and inspection 38 Design 35 Cleaning and inspection 24 Dismantling 36...
Introduction and safety instructions 2 Introduction and safety instructions Contents General ........................... 7 Safety ..........................7 Target group ........................7 Modifications ........................7 Tools ..........................7 Structure ......................... 7 Numbering ........................7 General instructions ....................... 8 Special instructions ......................8 2.10 Symbols on the trimmer ....................
Workshop Manual. of the actual unit in order to increase the basic Usage is made apparent in each section. understanding. Always use Husqvarna’s original: 2.7 Numbering • Spare parts Position references to components inside the •...
Introduction and safety instructions 2.8 General Instructions 2.9 Special Instructions The workshop where the trimmer is to be repaired The fuel used in the trimmer has the following must be equipped with safety equipment in hazardous properties: accordance with local regulations. •...
Introduction and safety instructions 2.10 Symbols on the trimmer 2.11 Symbols in the Workshop Manual The symbols below are embedded on the trimmer. This symbol warns of Choke Lever personal injury when the instructions are not followed. Refuelling Wear protective gloves. Stop switch Wear protective goggle.
Service tools Pos. Description Used for Order No. Air gap tool, ignition Setting ignition module 502 51 34-02 Piston stopper Locking the crank shaft 521 54 83-01 Electrode gap tool Adjusting spark plug gap 502 51 91-01 Puller assy Flywheel out 502 51 49-02 Rod assy Piston pin out or in...
Safety equipment 6 Safety equipment 6.1 Dismantling the muffler WARNING! Do not touch the muffler until it has cooled. Risk of burns. Remove the starter cover and clutch cover. Remove the muffler. See “7.1 Dismantling the starter” and figure 1. If the muffler is fitted with a spark arrestor mesh, this is removed.
Safety equipment 6.3 Dismantling the stop switch Carefully remove the stop switch using a flat screwdriver or similar tool. See figure 3 or figure 4 for R-handle. Disconnect the cables. Cleaning and inspection • Clean and check the power switch carefully. Replace parts that are broken or show signs of other defects.
Safety equipment 6.6 Dismantling the throttle Remove the screw holding the throttle handle against the shaft attachment, and the 4 screws holding the handle halves together. Lift off the right hand handle half and carefully note how the different parts are fitted. Fig 6 Lift off the catch (A) for unintentional full throttle and replace if needed.
Starter Starter 7.1 Dismantling the starter WARNING! The return spring lies tensioned in the starter and can fly out and cause personal injury with careless handling. Wear protective glasses. Starter, cylinder cover and half of the cover over the muffler is one unit. Remove all 8 screws including those holding the guard screen over the Fig 1 muffler.
Repair Instructions 7.2 Cleaning and inspection Clean component parts before assembling. Replace the return spring/starter pulley and starter cord, if necessary. NOTE! The return spring and starter pulley are supplied pre-assembled and are fitted in the starter housing as a single unit. Exercise care when opening the packaging Fig 5 so that the spring does not fly out.
Starter Tension the return spring. Pull the starter cord out completely and slow the starter pulley with your thumb. Lift the cord into the notch on the starter pulley. Now turn the starter pulley anticlockwise, 4 turns. See figure 9. Check the spring tension.
Repair Instructions Centrifugal clutch The centrifugal clutch has the task of transferring the power from the engine to the cutting equipment’s drive axle. As the name implies, it works according to a centrifugal principle. This means the clutch’s friction shoes are thrown outwards towards the clutch drum at a certain engine speed.
Centrifugal clutch Remove the 3 screws shown in figure 16, and lift off the cover over the clutch/flywheel. Fig 16 Remove the two screws holding the centrifugal clutch. See figure 17. Use the piston stop in order to loosen the screws. Lift off the clutch and both support washers.
Repair Instructions Electrical system The engine is equipped with an electronic ignition system completely without moving parts. Consequently, 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.
Electrical system If there is still no spark, remove the short-circuit cable from the short-circuit switch. Carefully remove the switch by inserting a small screwdriver or knife into the short end of the ignition switch. See figure 23. If the plug now sparks, the fault is either in the ignition switch or the short-circuit cable.
Repair Instructions Still no spark? Check other cables and connections for poor contacts (dirt, corrosion, cable breakage and damaged insulation). See figure 27. Make sure that the cables are correctly drawn and lie in the cable grooves. Do not forget to check the cables in the throttle too. See chapter “6.6 Dismantling the throttle”.
Electrical system 7.9 Dismantling the ignition system The following components must be dismantled for the ignition system to be accessible. • The starter cover with half of the cover over the muffler. • The spark plug. • The clutch cover and shaft. •...
Repair Instructions 7.10 Assembling the ignition system Check that the cast key in the flywheel and key way in the crankshaft are undamaged. Fit piston stop no. 521 54 83-01 in the spark plug hole. Fit the flywheel on the crankshaft. See figure 33. NOTE! Position the piston stop so it is clamped between the piston crown and the...
Do not blow the filter clean with compressed air. It can be damaged. Ensure that the filter is dry before refitting it. TIP! Use Husqvarna’s cleaning agent Active Cleaning no. 583 87 69-01. 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.
Repair Instructions 7.12 Tank venting The tank venting valve is fitted in a separate hose from the fuel tank and it is important that the valve functions for engine operation, especially at low speeds, i.e. to allow air into the tank but prevent fuel from being forced out.
Fuel system 7.14 Carburettor Removing the carburettor Remove the carburettor cover and blow the carburettor compartment clean with compressed air. Remove the air filter. Disconnect the throttle cable from the lever arm on the carburettor and from the guide in the air filter holder.
Repair Instructions 7.15 Dismantling the carburettor The metering unit Remove the 4 screws (A) and lift off the cover (B) and the pump bellows (C). Remove the non-return valve (D) using a small screwdriver. Lift off the diaphragm cover (E). Carefully remove the control diaphragm (F) and any gasket (G).
Fuel system Check the needle valve for damage on the tip and in the lever arm groove. Check the lever arm for damage to the groove for the needle valve and wear on the mounting points towards the control diaphragm. See figure 47.
Repair Instructions The blending unit Press out the main jet (A) with a suitable punch. Remember how far it is pressed into the carburettor housing. See figure 50. Remove the valves and dampers. If these components are worn, idling is disrupted. Always replace the valves and dampers at the same time.
Fuel system Fit the carburettor needles. Screw them in so that they just reach the bottom of the needle seat. See figure 54. Then screw them out according to the basic setting: H = 2 turns L = 1 turns NOTE! The H-needle is a little shorter than the L-needle.
Repair Instructions Fitting the carburettor Make sure the carburettor outlet and the distance piece flange are free from oil, grease, and adhesive film (from the old gasket). Connect the fuel hoses to the carburettor. Hold the carburettor against the air filter holder and push in the carburettor screws.
Fuel system The setting of the carburettor can vary a little depending on the humidity, temperature and air pressure. L = Low speed needle H = High speed needle T = Idle adjustment screw • The fuel quantity in relation to the air flow permitted by the throttle opening is adjusted by the L and H jets.
Repair Instructions Fine adjustment Idling speed T-screw Fine adjustment of the carburettor should be Let the engine idle for about 30 seconds or until carried out after the engine has been “run-in”. the speed has stabilized. Adjust the idling speed It is important that the air filter is clean and that T-screw until the engine idles without stopping.
Repair Instructions Cylinder and piston The cylinder and the piston are two of the components exposed to most strain in the engine. They must withstand, for example, high speeds, large temperature swings and high pressure. Moreover, they must be resistant to wear. Despite these tough working conditions, major piston and cylinder failure is relatively uncommon.
Cylinder and piston Push the gudgeon pin from the piston using punch no. 502 52 42-01. See figure 62. If the pin is too tight, carefully warm the piston. NOTE! Make sure the spacer washers on each side of the needle bearing are not misplaced.
For the best results we recommend However, the piston skirt has a darker colour Husqvarna two-stroke oil or ready-mixed caused by the hot combustion gases that are fuel that is specially developed for air- blown past the piston.
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. Piston ring breakage A too “lean”...
Repair Instructions 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.
Cylinder and piston Service tips Defect Action Broken cooling fins, damaged threads or sheared In severe cases – replace the cylinder. bolts by the exhaust port. Repair the threads using Heli-Coil. Seizure marks in the cylinder bore (especially by Polish the damaged area using a fine grade the exhaust port).
Repair Instructions 7.20 Assembling the cylinder and piston Lubricate the gudgeon pin’s needle bearing with a few drops of engine oil. Place a distance washer on each side of the needle bearing. Turn the countersunk end toward the needle bearing. Direct the arrow on the top of the piston towards the exhaust port.
Crankshaft and crankcase Crankshaft and crankcase The task of the crankshaft is to transform the reciprocating motion of the piston to rotation. This requires a stable design withstanding immense pressure and rotational and bending strain, as well as high rotational speed.
Repair Instructions Dismantle the ball-bearings from the crankcase halves. Heat the crankcase halves to 110°C using a hot air gun. See figure 70. Fig 70 Knock the crankcase half against a wooden block so that the ball-bearing falls out. See figure 71. Fig 71 Dismantle the sealing rings from the crankcase halves.
Crankshaft and crankcase Inspect the small end of the connecting rod. See figure 74. If seizure marks or discolouration are found in the bearing track the crankshaft must be replaced. Fig 74 Check the crank bearing. The connecting rod shall not have any radial play (up and down). See figure 75.
Repair Instructions Fit the crankshaft in the clutch side’s crankcase half. Lubricate the stub axle with a few drops of oil and carefully slide in the crankshaft in the ball- bearing so that the sealing ring is not damaged by the shoulder on the stub axle.
Bevel gear Bevel gear The angle gear has two purposes: The first is to gear down the engine’s high speed to better suit the lower speed a saw blade or trimmer requires to work efficiently. Secondly, the angle gear contributes towards the operator’s working stance so that it is comfortable and at the same time efficient.
Repair Instructions Dismantle the bearings from the output and input axles with the help of a small bearing puller. TIP! Hold the bearing puller in a vice so that it gains a better grip around the bearing. Fig 84 7.25 Assembling the angle gear Clean all component parts and replace if damaged or worn.
Troubleshooting 8.1 Troubleshooting The various faults that can affect a trimmer are divided into four groups. In each group the likely symptoms are given on the left and possible causes are listed on the right. The most likely faults are given first, and so on.
Troubleshooting Acceleration/Deceleration High speed Engine does Fuel filter blocked Poor Fuel filter blocked not accelerate The fuel hose blocked performance The fuel hose blocked Air in fuel ducts at high speed Air in fuel ducts Vacuum pulse leakage Incorrect/poor fuel Vacuum pulse duct blocked Vacuum pulse leakage Loose screw(s) on the pump...