Operator’s Manual. The assembly of other equipment or ac- The engine’s exhaust fumes are poisonous. Test run the engine cessories or spare parts not approved by Husqvarna can result outdoors. in the failure to meet these safety demands and that the person carrying out assembly bears responsibility for this.
Starter Dismantling Dismantling Remove the 8 screws and lift off the starter Starter, cylinder cover and half of the cover from the engine body. over the mufﬂ er is one unit. Remove all 8 screws including those holding the guard screen over the mufﬂ...
Starter Assembly Assembly Clean the component parts and assemble in Clean component parts before assembling. the reverse order as set out for dismantling. Replace the return spring/starter pulley and starter cord, if necessary. NOTE! The return spring and starter pulley are supplied pre-assembled and are ﬁ...
Starter Tension the return spring. Tension the return spring. Check the spring tension. Pull the starter cord out completely and slow the starter pulley with your thumb. Fit the starter on the engine body. Lift the cord into the notch on the starter pulley.
Electrical system Electrical system Contents Checking the ignition spark ______________________ 8 Dismantling __________________________________ 10 Assembly ___________________________________ 12...
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 difﬁ...
Electrical system When no spark is obtained, dismantle If there is still no spark, remove the short- the short-circuit cable from the ignition circuit cable from the short-circuit switch. switch. Prise up the switch by inserting a small Still no spark? screwdriver or knife into the short end of the ignition switch.
Electrical system Still no spark? Still no spark? Check other cables and connections for Check other cables and connections. poor contacts (dirt, corrosion, cable brea- kage and damaged insulation). 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.
Electrical system Separate the short-circuit cables. Separate both short-circuit cables. Remove the screws (A) and slide the Remove both screws (A), one on each throttle forwards. side of the throttle handle. Push the throttle forward onto the shaft. Loosen the screws and remove the shaft Loosen the screws and remove the shaft from the engine.
Electrical system Dismantle the centrifugal clutch. Remove the two screws holding the cen- trifugal clutch. Lift off the clutch and both support wash- ers. 502 71 27-02 Fit the piston stop no. 502 54 15-01 and Fit piston stop no. 502 54 15-01 in the remove the nut holding the ﬂ...
Electrical system Assemble the ignition module and adjust Assemble the ignition module. the air gap to 0.3 mm. Adjust the air gap. It should be 0.3 mm between the permanent magnets in the ﬂ ywheel and the ignition module. Assemble other parts in the reverse order as set out for dismantling.
Ensure that the ﬁ lter is dry before reﬁ tting it. TIP! Use Husqvarna’s cleaning agent Active Cleaning no. 505 69 85-70. Impregnate the ﬁ lter with air ﬁ lter oil. Impregnate the ﬁ lter with air ﬁ lter oil.
Fuel system Check that the slot in the non-return valve Remove the ﬁ lter housing (A) from the (B) is not damaged. bracket (D) on the carburettor cover using ﬂ at nose pliers. Clean the foamed plastic ﬁ lter (C). Remove the ﬁ...
Fuel system The carburettor’s design The carburettor’s design The carburettor can be divided into three The carburettor can be divided into three different functional units: the metering different functional units: the metering unit, the blending unit, and the pump unit. unit, the blending unit, and the pump unit.
Fuel system Dismantling the Dismantling the carburettor carburettor The metering unit The metering unit Remove the 4 screws (A) and lift off the Remove the 4 screws (A) and pull apart cover (B) and the pump bellows (C). the various parts for inspection and pos- sible replacement.
Fuel system Check the needle valve and the lever arm Check the needle valve for damage on the tip and in the lever arm groove. for damage or wear. Check the lever arm for damage to the Replace damaged components with new ones.
Fuel system The blending unit The blending unit Remove the main jet. Press out the main jet (A) with a suitable punch. Remember how far it is pressed into the carburettor housing. Check valves and dampers for wear. Remove the valves and dampers. If these components are worn, idling is disrupted.
Fuel system Fit the carburettor needles and adjust Fit the carburettor needles. them to the basic setting: Screw them in so that they just reach the bottom of the needle seat. H = 1.0 turn L = 1.5 turns Then screw them out according to the basic setting: H = 1.0 turn L = 1.5 turns...
Fuel system Assembly Assembly Connect the fuel hoses to the carburettor 1. Connect the fuel hoses to the carburet- and screw it on to the distance piece. tor. Do not forget the top screw! 2 Hold the carburettor against the air ﬁ...
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.
Fuel system Fine adjustment NOTE! Fine adjustment of the carburettor should be carried out after If the cutting equipment rotates while idling, the T-screw the engine has been “run-in”. It is important that the air ﬁ lter is must be turned anticlockwise until it stops rotating. clean and that the carburettor cover is ﬁ...
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 Replacing the clutch Replacing the clutch drum drum Pull both short-circuit cables apart and Pull the short-circuit cables apart and disconnect the throttle cable from the disconnect the throttle cable from the carburettor. carburettor. Remove both screws (A), one on each Remove the screws (A) and slide the side of the throttle handle.
Bevel gear The angle gear has two purposes: The ﬁ rst is to gear down the engine’s high speed to better suit the lower speed a saw blade or trimmer re- quires to work efﬁ ciently. Secondly, the angle gear contributes towards the operator’s working stance so that it is comfortable and at the same time efﬁ...
Bevel gear Dismantle the bearings from the output Dismantle the bearings from the output and input axles. 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. Assembly Clean all component parts and replace if damaged or worn.
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 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. NOTE! Make sure the spacer washers on each side of the needle bearing are not misplaced.
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%).
Cylinder and piston Piston scoring caused by heavy carbon deposits Too heavy carbon depositing can cause damage similar to that caused by insufﬁ cient lubrication. However, the piston skirt has a darker colour caused by the hot combus- tion gases that are blown past the piston. This type of piston damage starts at the exhaust port where carbon deposits can become loose and get trapped between the piston and the cylinder wall.
Cylinder and piston The guide pin for the piston ring has been Deep, irregular grooves caused by a loose Irregular grooves on the piston’s inlet side pushed up through the top of piston. circlip. Shown here on the piston’s inlet side. caused by a broken roller retainer.
Cylinder and piston Cause: Action: • Faulty air ﬁ lter. Small dust particles Fit a ﬁ ner grade ﬁ lter. pass through the ﬁ lter. Check the ﬁ lter carefully for holes and • The ﬁ lter is worn out due to too damage after cleaning.
Cylinder and piston Larger, harder particles that enter the engine cause serious damage to the under- side of the piston skirt. Cause: Action: • Air ﬁ lter damaged or missing. Fit a new air ﬁ lter. Regular service and inspection. •...
Cylinder and piston Wear tolerances Piston ring gap Piston ring groove Piston ring play Cylinder bore 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 of before checking the measure- before checking the measure-...
Cylinder and piston Check the carburettor’s distance piece/ heat shield (A) for cracks. Make sure the impulse channel (B) is open and that the gasket (C) is not dam- aged. Screw the distance piece to the cylinder and tighten the screws crosswise and diagonally.
Crankshaft and crankcase Crankshaft and crankcase Contents Dismantling ________________________________ 46 Inspecting the crankshaft ______________________ 47 Assembly _________________________________ 48...
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. In addition the connecting rod is exposed to large acceleration and retardation forces as it moves bet- ween the top and bottom dead centres.
Crankshaft and crankcase Dismantle the ball-bearings from the Dismantle the ball-bearings from the crankcase halves. crankcase halves. Heat the crankcase halves to 110°C using a hot air gun. Knock the crankcase half against a Knock the crankcase half against a wooden block so that the ball-bearing wooden block so that the ball-bearing falls out.
Crankshaft and crankcase Inspect the small end of the connecting Inspect the small end of the connecting rod. rod. If seizure marks or discolouration are found in the bearing track the crankshaft must be replaced. Check the crank bearing. Check the crank bearing. The connecting rod shall not have any radial play (up and down).
Crankshaft and crankcase Fit the crankshaft in the clutch side’s Fit the crankshaft in the clutch side’s crankcase half. 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.
Crankshaft and crankcase Full engine assembly sequence 1. Crankshaft with attached piston in the crankcase. 2. Flywheel on the crankshaft. 3. Drive cup on the crankshaft. 4. Centrifugal clutch on the ﬂ ywheel. 5. Cylinder. 6. Ignition module, air gap adjustment. 502 51 34-02 7.