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Safety equipment ............... 14 Repair instructions ..............24 Carburettor ................... 35 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 –...
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Introduction and safety regulations 2 Introduction and safety regulations List of contents General information ..............................5 Safety .....................................5 Target group ................................5 Modifications ................................5 Tools ....................................5 Structure ..................................5 Numbering ..................................5 General instructions ..............................6 Special instructions ..............................6 2.10 Symbols on the saw ..............................7 2.11 Symbols in the Workshop Manual ........................7 –...
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Workshop Manual. In order to increase the basic understanding, some Usage is evident from the respective section. sections include a Description of the unit in question. Always use Husqvarna’s original: 2.7 Numbering • Spare parts Position references to components inside the •...
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Introduction and safety regulations 2.8 General instructions 2.9 Special instructions The workshop where the chain saw is to be The fuel used for the chain saw has the repaired must be equipped with safety devices in following hazardous properties: accordance with local regulations. •...
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Introduction and safety regulations 2.10 Symbols on the saw 2.11 Symbols in the Workshop Manual The symbols below are embedded in the chain saw. This symbol warns of personal injury Choke control when the instructions are not followed. Use protective gloves. Refuelling Use protective goggles.
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Technical data 3 Technical data Displacement cm Cylinder bore Length of stroke Max. output/speed cubic inch Ømm/Øinch mm/inches kW/hp/rpm T525 27.0/1.65 35/1.38 28/1.1 1.1/9500 Electrode gap Air gap Carburettor type mm/inch mm/inch T525 0.65/0.026 0.4/0.016 Walbro WTA -37 Usable cutting...
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Technical data Idle speed Engage speed Spark plug T525 2900 4150 NGK CMR6A Volume fuel tank Capacity oil pump Volume oil tank Automatic oil Litres/US pint at 8000 rpm, Litres/US pint pump ml/min T525 0.19/0.4 0.17/0.36 Weight without bar and chain...
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Service tools 4 Service tools – English...
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Service tools The tools listed here are the service tools required for this model of chain saw. In addition to these tools, a normal kit of hand tools is required. Pos. Description Used for Order No. Assembling tool Assembling the sealing ring 577 70 16-01 Piston stop Lock crankshaft...
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Service data 5 Service data 7.9 ~ 10.8 Nm 16 mm 5.9 ~ 7.8 Nm 1.0 ~ 2.0 Nm 5.9 ~ 7.8 Nm 5.9 ~ 7.8 Nm 2.9 ~ 3.9 Nm 14.7 ~ 18.6 Nm 12 mm 1.2 ~ 2.5 Nm 1.0 ~ 1.5 Nm 1.0 ~ 1.5 Nm 2.5 ~ 3.9 Nm...
Safety equipment 6 Safety equipment List of contents Dismantling the chain brake ..........................15 Assembling the chain brake ..........................16 Dismantling the muffler ............................17 Assembling the muffler ............................17 6.5A Assembling the spike bumper ..........................18 6.5B Replacing the chain catcher ..........................18 Dismantling the start/stop switch ........................19 Assembling the start/stop control ........................19 Resistance test - stop function ..........................19 Dismantling the throttle lockout, throttle and spring .................20...
Safety equipment 6 Safety equipment 6.1 Dismantling the chain brake Release the brake by moving the kickback guard backwards. Loosen the bar nut and remove the clutch cover, saw chain and bar. See Figure 1 Fig 1 Activate brake tension by pulling back the knee joint as shown in Figure 2.
Safety equipment Remove the knee joint with the attached brake band from its attachment in the clutch cover. Cleaning and checking • Clean and check carefully all components. Parts must be replaced if cracked or show signs of other defects. Always use original spare parts.
Safety equipment Tighten the chain brake by using the saw’s front hand guard as a tool. Align the front section of the clutch cover with the front hand guard. Then pull the front hand guard back to disengage the brake. See Figure 9 Assemble the following parts: •...
Safety equipment 6.5A Assembling the spike bumper (accessories) The spike bumper is not fitted at the time of deliv- ery. Release the brake by moving the kickback guard backwards. Loosen the bar nut and remove the clutch cover, saw chain and bar. Fit the spike bumper as outlined in Figure 12a.
Safety equipment 6.6 Dismantling the stop switch Dismantle the start/stop switch with a screwdriver. See Figure 13. Check that the stop switch is intact. Cleaning and checking Fig 13 • Clean and check carefully all components. Parts must be replaced if cracked or show signs of other defects.
Safety equipment 6.9 Dismantling the throttle lockout, throttle and spring Release the chain brake by moving the kickback guard backwards. Dismantle the handle half by loosening the screws as outlined in Figure 17. Fig 17 Pull the stop switch up as outlined in Figure 18. Fig 18 Lift off the throttle lockout, throttle rod, throttle con- trol, spring and sealing and the throttle from their...
Safety equipment Cleaning and checking Clean and check carefully all components. Parts must be replaced if cracked or show signs of other defects. Always use original spare parts. Check that the recoil spring is intact and retains all its tension. 6.10 Assembling the throttle lockout, throttle and spring Do the procedure in chapter 6.9 Dismantling the...
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Repair instructions 7 Repair instructions List of contents Dismantling the starter ............................24 Changing a broken or worn starter cord ......................24 Tensioning the recoil spring ..........................24 Replacing a broken recoil spring .........................25 Assembling the starter unit ............................25 Testing the ignition module ..........................25 Dismantling the ignition module and flywheel .....................26 Assembling the ignition module and flywheel ....................28 Dismantling the centrifugal clutch ........................29...
Repair instructions 7 Repair instructions 7.1 Dismantling the starter Loosen the screws that hold the starter against the crankcase and remove the starter. See Figure 1. Fig 1 Pull out the cord about 30 cm and release the tension in the recoil spring by letting the starter pulley slowly rotate anti-clockwise.
Repair instructions 7.2 Replacing a broken or worn starter cord When the starter cord is worn and must be replaced, the tension in the recoil spring must be released. Pull out the starter cord about 30 cm. Release the tension in the recoil spring by letting the starter pulley rotate anti-clockwise.
Repair instructions 7.4 Replacing a broken recoil spring WARNING! Exercise care to ensure the spring does not fly out and cause perso- nal injury. Wear protective goggles. Loosen the screw as outlined in Figure 8 and re- move the starter pulley and the spring cassette. Replace the faulty spring cassette.
Repair instructions 7.7 Dismantling the ignition module and flywheel Dismantle the following: • Remove the cylinder cover. • Detach the spark plug cable. • Remove spark plug • Remove the starter and air guide rail. • Remove the flywheel cover Remove the spark plug cap and spark plug.
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Repair instructions Knock out a few of the pins in the tool if it does not match up with the flywheel. Press against the flywheel while the flywheel nut is loosened using a suitable socket spanner. See figure 15. Fig 15 Screw the mandrel on the crank shaft journal.
Repair instructions 7.8 Assembling the ignition module and the flywheel Fit the flywheel onto the crankshaft journal. Turn the flywheel until the key fits into the key slot on the axle. See figure 18. Fig 18 The ignition module must be fitted as follows: Pull the ignition module cabling through the crankcase and place the ignition module in position.
Repair instructions 7.9 Dismantling the centrifugal clutch Release the brake by moving the kickback guard backwards. Loosen the bar nut and remove the clutch cover, saw chain and bar. See Figure 22. Fig 22 Dismantle the cylinder cover, remove the spark plug cap and unscrew the spark plug.
Repair instructions 7.10 Assembling the centrifugal clutch Hook the springs into the clutch shoes. Press in the clutch hub from above while bending back the clutch shoes around the clutch hub as shown in Figure 26. Screw in the clutch (anti-clockwise) until it stops. Then tighten the clutch using a 13 mm socket spanner.
Repair instructions Remove the pump drive wheel and pump cover. See Figure 29. Fig 29 Remove the oil tank cap. Pull out the oil hose and remove the oil filter. See Figure 30. Loosen the screws and remove the oil system. See Figure 31.
Repair instructions 7.13 Carburettor WARNING! The fuel used in the chain saw has the following hazardous properties: 1. The fluid and its vapour are poisonous. 2. Can cause skin irritation. 3. Is highly inflammable. Description The images for this description do not correspond to the carburettor on the chain saw.
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Repair instructions Function The carburettor functions differently in the following modes: Cold start mode In cold start mode the choke valve (D) is comple- tely shut. This increases the vacuum in the carbu- rettor and fuel is easier to suck from all the diffuser jets (E, F and G).
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Repair instructions Dismantling the carburettor Dismantle the air filter and air filter cover. See Figure 40. Fig 40 Loosen suction hose (A).Pull out the purge (B). To remove the carburetor (C), remove the carburetor from the chassis and remove the link rod (D). See Figure 41.
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Repair instructions Loosen the screws (A) and the washers (B). Remove top cover (C). Remove control diaphragm (D). Remove gasket (E). See Figure 42. Loosen the screw (F) and lift out the needle valve (J) with the lever arm (G), the axle (H) and the spring (I).
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Repair instructions Assembling the carburettor Observe cleanliness when assembling the carburettor. The slightest contamination can cause malfunctions. If throttle and choke valves with shafts, lever arms and springs have been removed, these must be assembled. The springs are tightened 1-2 turns. Lubricate the shaft bearings using a light oil.
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Repair instructions Pressure testing the carburettor Pressure testing should be carried out with the carburettor fully assembled. The test must always be done after the carburettor has been repaired, but can also be carried out when troubleshooting before the carburettor is taken apart. Test 1 See Figure 44 and carry out the following check: Connect pressure tester to the carburettor fuel...
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Repair instructions Assemble on the saw Hook the link rod (D) to the carburetor as outlined in Figure 45. Attach the two inlet manifolds to their corresponding grommet. Slide the purge (B) into place. Attach the suction hose (A) as outlined in Figure 45.
Repair instructions 7.14 Dismantling the intake system Remove the air filter cover, cylinder cover. Remove the screw (A). Remove the bolt (B). Remove the antivibration element (C). Fig 47 Remove the two screws holding the grip cover. Remove the grip holder. See Figure 48. Fig 48 Remove the screw and the front handle.
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Repair instructions 11. Press down the inlet pipe through the right handle and pull up the right handle. Disconnect all the hoses. See Figure 50. Fig 50 12. Remove the inlet pipe. Remove the screws and lift up the intake manifold. See Figure 51. Fig 51 Cleaning and checking Clean and check all parts carefully.
Repair instructions 7.15 Assembling the intake system NOTE! It is very important that the intake sys- tem is sealed. Otherwise the engine may seize up. Follow the chapter 7.14 Dismantling the intake system in the reverse order. Make sure to use the correct torque.
Repair instructions 7.16 Dismantling the tank unit WARNING! The fuel used for the chain saw has the following hazardous properties: The liquid and its fumes are poisonous. Can cause skin irritation. Is very flammable. Follow the instructions in chapter 7.24 Disman- tling the piston and cylinder, step 1 - 8.
Repair instructions 7.18 Aerating the fuel tank The two-way valve has the following properties: • Checks opening pressure in both directions, which prevents a positive pressure or a vacuum developing in the fuel tank and impairing engine performance. This also prevents fuel leakage.
Repair instructions 7.19 Replacing the fuel filter NOTE! Fluted pliers may not be used with the fuel hose. They can cause material damage resulting in damage to the fuel hose. When replacing the fuel filter, the old fuel filter must be taken out of the tank unit using the special 502 50 83-01 tool.
Repair instructions NOTE! Fluted pliers may not be used with the fuel hose. They can cause material damage resulting in damage to the fuel hose. 7.22 Replacing the fuel hose Remove the air filter cover, air filter and carburetor. Remove the fuel filter as outlined in Figure 55. Carfully pry open the engine case cover with a flat screwdriver.
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Repair instructions Dismantling rear damper Remove the air filter cover, cylinder cover Remove the screw (A). Remove the bolt (B). Remove the antivibration element (C). Fig 60 Dismantling bottom damper Remove the two screws holding the grip cover. Remove the grip holder. See Figure 61. Remove the screw holding the front handle.
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Repair instructions Dismantling top damper Remove the throttle components. Remove the air filter. Remove the carburetor. Remove the engine case cover. Press down the inlet pipe through the right handle and pull up the right handle. Disconnect all the hoses. See Figure 63. Fig 63 Remove the safety wire (B).
Repair instructions 7.24 Dismantling the piston and cylinder Dismantle the following: • Air filter cover and air filter • Carburetor • Starter assembly • Clutch cover • Cylinder cover • Muffler • Engine case cover • Front Handle • Handle •...
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Repair instructions Use the special tool 502 51 94-01 to remove the flywheel. See Figure 68. Follow the instructions in chapter 7.7 Dismantling the ignition module and flywheel. Fig 68 Remove the impulse hose from the joint. See Figure 69. Fig 69 Remove the pump drive wheel and pump cover.
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Repair instructions Remove the screws and remove the oil system. See Figure 71. Fig 71 Remove the inlet pipe cover. Loosen the screws holding the inlet pipe and re- move the inlet pipe. Remove the screws attaching the the crankcase and cylinder to the chassis.
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Repair instructions Remove the screws holding the crankcase parts. Carfully pull the crankcase halves apart. Two guide pins keep the crankcase halves together. Lift out the connecting rod with the piston. See Figure 74. Fig 74 Use a flat screwdriver to remove the circlips from the gudgeon pin.
Repair instructions Faults and causes Score marks on the piston (A). Leakage, check not carried out. Too low octane rating in the petrol. Too little or incorrect oil in the fuel. Carbon deposits (B) Too much or incorrect oil in the fuel. Fig 77 Piston ring breakage Piston ring worn out.
Repair instructions 7.26 Pressure testing the cylinder Remove the following parts before you do a pressure test of the crankcase and cylinder: • Clutch cover • Air filter cover • Air filter • Muffler Slide the cover plate (A) (502 54 11-02) under the carburetor and tighten, using the carburetor screws (B) as outlined in Figure 80.
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Repair instructions Cleaning and checking Clean all parts and scrape off all gasket remains from the contact surfaces on the crankcase halves. Check the following: • That the big-end bearing does not have any radial play. Axial play is permitted. See Figure 82.
Repair instructions 7.28 Replacing the crankshaft bearing and sealing ring Use the 576 66 64-01 (A), 576 95 45-01 (F) and 725 23 80-51 (E) tools to assemble the crankcase bearing (B) and sealing ring. Fit the service tool as outlined in Figure 85.
Repair instructions Place the guide pin in the crankcase half of the flywheel. Fit the 577 70 16-01 assembling tool to the crankshaft journal. See Figure 89. Fig 89 Put the crankshaft in position and fit the other crankcase half. Apply liquid gasket between the surfaces of the crankcase.
Repair instructions 7.30 Repairing damaged threads Damaged threads can be repaired using a threading plug. The slotted section in the thread plug is screwed in place first as this is the cutting part. Request to repair a thread where a PL5 screw was used.
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Troubleshooting 8 Troubleshooting List of contents Troubleshooting ................................59 Troubleshooting techniques ..........................61 – English...
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Troubleshooting 8.1 Troubleshooting The different faults which may occur on the chain saw are divided into four groups. Within each group pos- sible operating faults are listed to the left while the probable fault alternatives are listed to the right. The most likely fault is listed first, etc.
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Troubleshooting High speed Will not "four Tank venting clogged stroke" The fuel filter is clogged Does not run Adjust the H-screw The fuel hose is clogged at full throttle Blocked air filter Loose or defective fuel hose Tank venting clogged Impulse channel leaking The fuel filter is clogged Blocked impulse channel...
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8.2 Troubleshooting techniques In addition to faults given in the above schematic, troubleshooting can be carried out on a specific component or specific chain saw system. The different procedures are described in respective sections, see the list of contents, and are as follows: •...