CONTENTS Page HUSQVARNA LITERATURE 2. SPECIAL FUNCTIONAL COMPONENTS K 960 COMPONENTS – ORIENTATION 4. DISMANTLING INTO BASIC MODULES 5. STARTER 6. IGNITION SYSTEM 7. FLYWHEEL 8. AIR FILTER 9. INLET SYSTEM 10. FUEL SYSTEM 11. CARBURETTOR 12. DECOMPRESSION VALVE 13. CYLINDER/PISTON 14.
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This arrangement means that as a mechanic, Workshop manual K 960 at least until you have learnt the basic composi- tion of the machine, you need to start with the HUSQVARNA CONSTRUCTION PRODUCTS chapter “Dismantling into Basic Modules”...
SPECIAL FUNCTIONAL COMPONENTS New technical solutions Husqvarna K960 is the first model in a new generation of power cutters with a number of new technical solutions: New engine technology – Dual Charge The cylinder, piston and carburettor are radically changed.
DISMANTLING INTO BASIC MODULES Basic modules This chapter shows how the machine is built up of basic modules, for example, the starter, carburettor, air filter system, etc. The purpose is to illustrate how you can easily and effectively dismantle and assemble the machine in its basic modules.
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DISMANTLING INTO BASIC MODULES Air filter 1. Loosen both screws on the guard and remove the guard. 2. Lift off the filter base. 3. Carefully lift up the paper filter so that dust does not fall down into the inlet bend. Cylinder cover 1.
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DISMANTLING INTO BASIC MODULES Assembly 6. Pre-assemble the components as illustrated. Slide the screws slightly past the contact face. 7. Note the partition wall in the inlet manifold. Note that the marking “UP” must face upwards, if the partition wall was loosened when dismantling the car- burettor.
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DISMANTLING INTO BASIC MODULES Vibration dampening Several service procedures can be facilitated by splitting the machine at the vibration dampening element. Perform the following before splitting: – dismantle the air filter unit and cylinder cover – dismantle the starter – loosen the cable lug on the ignition module and the stop button and remove the air duct –...
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STARTER Replacing the starter cord Dismantle the starter. Eliminate the spring force from the return spring 1. Pull out the starter cord approximately 12 in./30 cm. Hold the starter pulley with your thumb and place the cord in the cut-out on the starter pulley. 2.
STARTER Starter pulley 1. Dismantle the centre bolt and lift off the starter pulley. Clean the surfaces between the starter pulley and the spring cassette. Assembly 2. Lubricate the hub with grease (arrows). Preferably also apply some grease around the starter pulley hub so that the grease seals against the spring cassette.
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STARTER Starter pawls Function In principle the starter pawls have two positions that are determined by the centrifugal force generated by the rotation of the flywheel. When the engine is at a standstill the springs push the starter pawls towards the centre, which when starting then grip the starter pulley's metal sleeve.
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It is insensitive to moisture and dirt. The design is point such that the ignition point does not need to readjustment. Husqvarna K960 has integrated overspeed protection in the electronic unit that limits the engine's speed to 9,300 rpm. The ignition system consists of the primary coil (A) and secondary coil (B) which are both surround ed by the iron core (C).
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IGNITION SYSTEM Trouble shooting Examine the ignition system first when the engine does not start. Check the ignition spark Earth the spark plug against the cylinder. Move the stop button to the operating position. Pull the starter handle as with starting.
IGNITION SYSTEM Test the short-circuit cable and stop switch Test using a measurement instrument or the following simple solution: Connect a battery in series with a test lamp to the short-circuit cable and engine body. Watch the test lamp while testing the function of the stop switch.
Tool 502 51 49-02 Tool 502 51 49-02 502 51 49-02 The special tool is used to A special tool from Husqvarna is dismantle and assemble the required to dismantle and assemble the flywheel. flywheel. The tool fits virtual all fly - wheels on Husqvarna power cutters.
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FLYWHEEL Check the keyway and key Check the keyway and key Note that the key in the fly - Note that the key in the flywheel is cast wheel is cast and can not be and can not be replaced. If the key is replaced.
AIR FILTER Function Husqvarna Active Air Filtration is a filter system that effectively purifies the air to the engine in three separate steps and according to three different purification principles: 1. Centrifugal cleaning is the first step in the purification of the inlet air.
INLET SYSTEM Inlet manifold The inlet manifold joins the carburettor and cylinder. The inlet manifold insulates the carburettor from cylinder heat and also provides the carburettor with vibration damping. The inlet manifold has separate ducts for the fuel-air mixture and clean air. The impulse channel (A) leads pressure variations from the crankcase to the carburettor's pump diaphragm.
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INLET SYSTEM Assembly Assembly 8. Important when reassembly: 8. It is important that the clamp is Screw the clamp together com- screwed together completely in against pletely in against the spacer the spacer tube in order for the inlet tube. manifold to seal fully against the cylin- der.
FUEL SYSTEM Fuel filter Fuel filter Dismantle the filler cap. Dismantle the filler cap and pull out the section holding the filler cap in position Catch the fuel hose with the when fuelling. help of tool 502 50 83-01. Catch the fuel hose with the help of tool 502 50 83-01.
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FUEL SYSTEM Exclude the carburettor as Exclude the carburettor as the the cause of the leakage cause of the leakage Plug the hose by the carburettor Plug the hose by the carburettor and and redo the pressure test. redo the pressure test. If the hose is intact, the carburettor must be checked.
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FUEL SYSTEM Tank venting hole Tank venting hole Check by blowing through the If the non return hose is not mal - hose. functioning, blocked tank venting may be due to a clogged venting hole in the tank. This is simply checked by blowing though the hose.
15. Needle valve for pressure regulator Dual Charge™ Split venturi K960 is the first power cutter from Husqvarna with a split venturi. An over- rich fuel/air mixture is produced in the lower half while clean air passes through the carburettor in the upper half.
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CARBURETTOR Functional test Functional test Pressure tester Pressure tester 501 56 27-01 501 56 27-01 The pressure tester has a pump piston The pressure tester is sup plied that is operated with one hand. with an adapter nipple for small The pressure tester is supplied with an sizes.
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CARBURETTOR Measurement chamber Note the interrelated positions of the components when dismantling, as they can be reassembled in the wrong order. The gaskets A are identical. Measurement chamber – function The measurement chamber has two chambers: The air chamber (towards the cover) and the fuel chamber (towards the carburettor body).
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CARBURETTOR Pump unit Function The pump diaphragm (A) is driven by the pressure variations in the crankcase, which are led to the top of the pump diaphragm. The fuel on the underside of the diaphragm is pumped to the valves (B). The counter pressure of the measurement chamber diaphragm against the needle valve in the measurement chamber controls the valves' degree of opening and the quantity of fuel pumped into the measurement chamber's...
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CARBURETTOR Valve axles Valve axles Check that there is no radial play Leakage from the valve axles results in on the valve axles. Replace parts incorrect fuel/air mixture and to dust if necessary. penetration in the engine. Check that there is no radial play on the valve axles.
DECOMPRESSION VALVE Decompression valve Function The decompression valve reduces the compression in the cylinder when starting. A limited quantity of fuel/air mixture leaks out through the decompression valve, as shown in fig. A. As soon as the engine fires the valve will close due to the combustion pressure, as in fig.
CYLINDER/PISTON Compression test Compression test The test indicates leakage from The compression test indicates leakage the combustion chamber. from the combustion chamber. If the Close the decompression machine lacks engine power and is diffi- valve or fit the sealing plug cult to start this may be due to poor 503 55 22-01.
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CYLINDER/PISTON Remove the cylinder base gasket. Remove the cylinder base gasket. Tool kit 502 50 70-01 Tool kit 502 50 70-01 The tool kit contains piston The tool kit contains, to the left, piston ring compressors, a piston stop, ring compressors to press together the and a support plate for the piston rings when assembling.
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CYLINDER/PISTON Gudgeon pin punch Gudgeon pin punch 505 38 17-05 Used to dismantle and assemble The gudgeon pin punch is used to press the gudgeon pin. out the gudgeon pin. It is also used for assembly. 505 38 17-05 Dismantle the gudgeon pin Dismantle the gudgeon pin Push out the gudgeon pin by Push out the gudgeon pin in any direc-...
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CYLINDER/PISTON Wear tolerances Wear tolerances Cylinder Cylinder Inspect the cylinder bore against Inspect the cylinder bore against the the light. As long as the surface light. As long as the surface layer has not layer has not been broken been broken through, the cylinder is in through, the cylinder is in working order.
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The cause of engine failure is often difficult to establish, primarily when the machine's history is not known. The typical cases below can provide some guidance. (Pistons from Husqvarna K750.) Normal wear Typical normal wear is easiest to see on the piston sections that face the exhaust and inlet sides.
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CYLINDER/PISTON Assembly Assembly Oil in Oil in Oil in bearings and piston rings New or cleaned bearings and piston rings with 2-stroke oil. should be oiled in with 2-stroke oil before assembly to initially ensure satisfactory lubrication. The arrow pointing The arrow pointing towards the towards the exhaust port exhaust port...
CRANKCASE Leakage test A leaking crankcase results in reduced crankcase compression. A typical sign is that the machine is difficult to start. Tools 502 71 39-01 506 34 45-01 Tools 502 71 39-01 and 506 34 45-01 are required during the leakage test to seal the exhaust port and inlet port.
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CRANKCASE Crankcase seals Tools The puller 504 91 40-01, assembly taper 505 38 17-23 and the assembly punch 502 50 82-01 are needed to change the crankcase sealing rings. 504 91 40-01 505 38 17-23 502 50 82-01 Dismantling 1. Press down the puller and tighten the puller's conical thread in the seal ing ring.
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Tools Tools A universal puller (504 90 90-02) and a A universal puller and a special special tool (grip plate) from Husqvarna tool are needed to split the (544 06 00-02) are needed to spilt the crankcase. crankcase. 504 90 90-02...
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CRANKCASE If the bearing releases from the crankcase 531 00 48-67 Normally the bearing should release from the crankshaft during dismantling. The bearing is dismantled from the crankshaft using the puller 531 00 48-67. 1. First fit the puller plate behind the bearing.
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CRANKCASE Crankshaft Tools Use the tool kit 544 10 36-02 to press the crankshaft into the bearing, after first fitting this in the relevant crankcase half. The threaded mandrel for the clutch and flywheel side is M12V and M8x1, respec- tively.
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CLUTCH Dismantling Dismantling Dismantle the cutting head, the Dismantle the cutting head, the rear belt rear belt guard, the air filter guard, the air filter cover, and the filter cover, and the filter base. base. Fit the piston stop Fit the piston stop Lock the crankshaft's travel by fitting the piston stop 504 91 06-05 instead of the spark plug.
CLUTCH Clutch springs Dismantling Secure the clutch in a vice. Position a heavy screwdriver against the spring hook. A hand movement against the screwdriver will get the spring hook to move without unhooking. Press out the spring hook using a punch. Assembly Preassemble the springs in the part of the shoes with less space.
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Bearing replacement – needle bearing For a long time, a clutch drum with needle bearing has been the standard design on Husqvarna petrol-driven power cutters. The needle bearing is lubricated via a channel in the crankshaft from the crankcase. In 2008 the needle bearing is being replaced with a ball bearing. Please note that machines with a needle bearing cannot be fitted with a ball bearing as the crankshaft and clutch drum are of different dimensions.
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CLUTCH Bearing replacement – ball bearing A clutch drum with permanently lubricated ball bearing is being introduced on the K960 in 2008. The drilled channel in the crankshaft that provided the earlier needle bearing design with lubrication is being discontinued. Tools The tool kit 504 56 79-01 is needed to replace the ball bearing of the clutch drum.
CUTTING HEAD Dismantling Dismantling Dismantle the cutting head Dismantle the cutting head from the from the machine. machine. This chapter describes dismantling of the cutting head components and has instructions for replacing the blade shaft bearing at the end. Lock the belt pulley with a Lock the belt pulley with a mandrel and mandrel and dismantle the dismantle the centre screw.
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CUTTING HEAD Lift the blade guard off the Lift the blade guard off the bearing bearing housing. housing. Check that the grooved rings are Check that the grooved rings for the intact. blade guard's locking mechanism are Also check that the rubber intact.
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CUTTING HEAD Place the triangle of the special Place the triangle of the special tool in tool in the cut-out of the bearing the cut-out of the bearing housing inten- housing intended for it. ded for it. Knock out the entire bearing Knock out the entire bearing unit with a unit with a plastic hammer, plastic hammer.
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CUTTING HEAD Assembling the inner bearing Place the bearing on the support plate and hold it under the bearing housing. Insert the screw through the washer on the upper side and assemble the screw in the support plate on the underside. Lock the screw and turn the nut until the bearing reaches the stop in the bearing housing.
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CUTTING HEAD Fit the belt pulley Note that the axle and the belt pul ley have a profile that means that the belt pulley must be turned cor rectly when assembling. Do not forget the washer between the bearing and the belt pulley! 1.
FRICTION RETARDER The friction retarder is being introduced as standard equipment on the K960 in 2007. Function The design is a centrifugal brake where the brake shoes (A) are pressed against the brake drum (B). The spring (C) transmits a braking effect to the brake shoes.
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FRICTION RETARDER Dismantling the retarder Remove the four screws that hold the centrifugal unit against the belt pulley. Release the centrifugal unit from the belt pulley by pressing the guides down (black and white arrows). Use compressed air to clean off dust, as required.
HANDLE Rear handle Rear handle Lock the throttle against Lock the throttle against uninten- unintentional activation tional activation Faulty function must be rectified. Check the function of the lock. The The machine must be split throttle should be locked in idling mode. at the vibration dampening Not until the lock on top of the handle element to perform service work...
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531 03 06-23 Flywheel puller Pressure tester Puller for the flywheel. Fits all Kit consisting of pump with petrol-driven Husqvarna cutters. pressure gauge and nozzles, hose and sealing plug for universal use. Dismantling the flywheel. ● Leakage testing the crankcase.
TOOLS = Service action ● 503 55 22-01 544 10 36-02 Sealing plug Bearing press Replaces the decompression valve. Dismantling the main bearing. ● ● Leakage testing the crankcase. ● Assembly of the crankshaft. ● Assembly of the clutch's support washer on the crank shaft.
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