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Husqvarna T425 Workshop Manual
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Husqvarna T425 Workshop Manual

Husqvarna T425 Workshop Manual

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Workshop manual
T425
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Summary of Contents for Husqvarna T425

  • Page 1 Workshop manual T425 English...

  • Page 3: Table Of Contents

    Safety equipment ..........16 Repair instructions ..........26 Carburettor ............35 Trouble shooting ..........53 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 -...

  • Page 4: Index

    Index Index Modifi cations 7 Numbering 7 Carburettor 35 Safety 7 Adjusting the carburettor 44 Special Instructions 8 Assembly 40 Structure 7 Cleaning and checking 39 Symbols in the Workshop Manual 9 Design 35 Symbols on the saw 9 Dismantling 37 Target group 7 Function 36 Tools 7...
  • Page 5 Index Tank unit 45 Dismantling 45 Technical data 10 Throttle lockout, throttle and spring 23 Cleaning and checking 21 Cleaning and checking 24 Dismantling the throttle lockout, throttle and spring 23 Trouble shooting 54 Trouble shooting techniques 55 Vibration damping system 46 Assembly 46 Cleaning and checking 46 Dismantling 46...

  • Page 6: Introduction And Safety Regulations

    Introduction and safety regulations 2 Introduction and safety regulations List of contents General information ......................7 Safety ..........................7 Target group ........................7 Modifi cations........................7 Tools ..........................7 Structure .........................7 Numbering ........................7 General instructions ......................8 Special instructions ......................8 2.10 Symbols on the saw .......................9 2.11 Symbols in the Workshop Manual ..................9 - English...
  • Page 7 Workshop Manual. sections include a Description of the unit in ques- Usage is evident from the respective section. tion. Always use Husqvarna’s original: 2.7 Numbering • Spare parts Position references to components inside the fi g- •...
  • Page 8 Introduction and safety regulations 2.8 General instructions 2.9 Special instructions The workshop where the chain saw is to be re- The fuel used for the chain saw has the following paired must be equipped with safety equipment in hazardous properties: accordance with local regulations.
  • Page 9 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. Refuelling Stop button Filling up saw chain oil English -...

  • Page 10: Technical Data

    3 Technical data Displacement Cylinder diameter Length of stroke Max. output/speed cm3/cubic inch Ømm/Øinch mm/inches kW/hp/ rpm T425: 25.4 / 1.55 34 / 1.34 28 / 1.10 0.96 / 1.29 / 9,000 Electrode gap Ignition system Air gap Carburettor type...
  • Page 11 Technical data Idle speed Engage speed Spark plug T425: 2,900 3,800 NGK BPMR 7A Champion RCJ 7Y Volume fuel tank Capacity oil pump at Volume oil tank Automatic oil pump Litres/US.pint 9,000 rpm, Litres/US.pint ml/min T425: 0.23/0.48 0.16/0.34 Weight without bar and chain Weight with bar and chain...

  • Page 12: Service Tools

    Service tools 4 Service tools - English...
  • Page 13 Service tools Pos. Description Used for Order No. Clutch tool Centrifugal clutch 505 05 99-01 Piston stop Locking the crankshaft 504 91 06-05 Hook for fuel fi lter Lifting out the fuel fi lter 502 50 83-01 Allen key, 4 mm For M5 bolts 502 50 87-01 Allen key, 4 mm...

  • Page 14: Service Data

    Service data 5 Service data The numbers by the components to be assembled with screws state the tightening torque in Nm. ▲ = Lubricate with two-stroke oil. ■ = Lubricate with engine oil. ● = Lubricate with grease. ❑ = Glued using 2 component adhesive. ❍...
  • Page 15 Service data English -...

  • Page 16: Safety Equipment

    Safety equipment 6 Safety equipment List of contents Dismantling the chain brake ...................17 Assembling the chain brake ....................18 Dismantling the muffl er ....................20 Assembling the muffl er ....................20 Replacing the chain catcher ...................20 Dismantling the stop switch ....................21 Assembling the start/stop switch ..................21 Resistance test - stop function ..................22 Dismantling the throttle lockout, throttle and spring ............23 6.10...

  • Page 17: Dismantling The Chain Brake

    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, chain and bar. Fig 1 Release the brake by pushing the kickback guard forwards.

  • Page 18: Assembling The Chain Brake

    Safety equipment Loosen the nut E, washer D, spring C, sleeve B and screw A. To remove the knee joint G and H, use a punch to press out the pin F. Pull out the pin J to loosen the brake band K and knee joint H (see fi...
  • Page 19 Safety equipment Insert the screwdriver into the end of the spring and press the spring together while pushing it down with the fi nger. Fig 11 Hold the spring in place with the fi nger and remove the screwdriver. Insert the screwdriver straight from above and press down until the spring catch- es against the cut-out edge.

  • Page 20: Dismantling The Muffl Er

    Safety equipment 6.3 Dismantling the muffl er WARNING! Do not touch the muffl er before it has cooled down. Risk of burns. Release the brake by moving the kickback guard backwards. Loosen the bar nut and remove the clutch cover, chain and bar.

  • Page 21: Dismantling The Stop Switch

    Safety equipment 6.6 Dismantling the start/stop switch Bend the start/stop switch loose with a screwdriver (see fi gure 20). Check that the start/stop switch is intact. Cleaning and checking Fig 20 Clean and check carefully all components. Parts must be replaced if cracked or showing signs of other defects.

  • Page 22: Resistance Test - Stop Function

    Safety equipment 6.8 Resistance test - stop function Remove the starter, see “Dismantling the starter”. Remove the cover A (see fi gure 24) by loosening the two screws. Bend up the yellow cover paper C to be able to reach screw D for testing (see fi gure 25).

  • Page 23: Dismantling The Throttle Lockout, Throttle And Spring

    Safety equipment 6.9 Dismantling the throttle lockout, throttle and spring Unscrew the air fi lter housing and air fi lter holder. Dismantle the handle part by loosening screw A. Remove the throttle lockout B. Fig 27 Loosen the choke. Fig 28 Lift out the carburettor with a pair of fl...

  • Page 24: Assembling The Throttle Lockout, Throttle And Spring

    Safety equipment Unhook the carburettor from the throttle actuator rod. Fig 31 Remove the throttle actuator rod D. Press out pin E to loosen the throttle F and spring G. Fig 32 Cleaning and checking • Clean and check carefully all components. Parts must be replaced if cracked or show signs of other defects.
  • Page 25 Safety equipment Insert the throttle actuator rod into the carburettor. Fig 34 Turn the carburettor back half a revolution. Fig 35 Hold the carburettor with a pair of fl at nosed pliers and make sure the nipples are pushed down prop- erly into the inlet- and fuel connections.

  • Page 26: Repair Instructions

    Repair instructions 7 Repair instructions List of contents Dismantling the starter ....................27 Changing a broken or worn starter cord .................28 Loading the return spring ....................29 Replacing a broken return spring ...................29 Assembling the starter ....................29 Testing the ignition module .....................30 Dismantling the ignition module and fl...

  • Page 27: Repair Instructions

    Repair instructions 7 Repair instructions 7.1 Dismantling the starter Dismantling the air fi lter cover. Fig 1 Loosen the starter with the screws 2xA and 4xB. Fig 2 Loosen the air conductor from the starter. Fig 3 Pull the cord out about 30 cm and lift it into the notch on the starter pulley’s outer edge.

  • Page 28: Changing A Broken Or Worn Starter Cord

    Repair instructions Undo the screw in the centre of the pulley and remove the pulley and the spring cassette. Fig 6 Cleaning and checking Clean the parts and check: • Starter cord. • That the starter pawls on the fl ywheel are in- tact, i.e.

  • Page 29: Loading The Return Spring

    Repair instructions 7.3 Loading the return spring Wind approx. 3 turns of the starter cord onto the pulley. Fit the bolt into the centre of the starter pul- ley, tightening torque 2-3 Nm. Pull the starter cord up into the notch in the starter pulley and turn the pulley about 3 turns clockwise.

  • Page 30: Testing The Ignition Module

    Repair instructions 7.6 Testing the ignition module In case of malfunctioning ignition system, the ignition module must be tested before the ignition system is removed. Check the ignition module as follows: • Unscrew the spark plug. Connect test spark plug 505 71 13-01 to the ignition cable and clamp the test spark plug onto the cylinder.

  • Page 31: Assembling The Ignition Module And Fl Ywheel

    Repair instructions Loosen fl ywheel nut E with a suitable socket wrench and then remove the nut (see fi gure 15.) Knock on the mandrel F with a suitable metal ham- mer until the fl ywheel comes off the shaft. Remove mandrel and fl...

  • Page 32: Dismantling The Centrifugal Clutch

    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, chain and bar. Fig 18 Unscrew the spark plug and put in piston stop A. Fig 19 Loosen the clutch using tool 505 05 99-01 (B) and a suitable socket wrench or combination spanner.

  • Page 33: Assembling The Centrifugal Clutch

    Repair instructions Cleaning and checking • Clean and check all parts carefully. Parts must be replaced if cracked or showing signs of other defects. Always use original spare parts. Fig 23 7.10 Assembling the centrifugal clutch Hook the springs into the clutch shoes. Press in the clutch hub from below while bending back the clutch shoes around the clutch hub as shown in fi...

  • Page 34: Dismantling The Oil Pump And Screen

    Repair instructions 7.11 Dismantling the oil pump and screen Dismantle the centrifugal clutch as in “Dismantling the centrifugal clutch”. Loosen the chain catcher screw B, halfway. Re- move the chain guide plate A. loosen screws C and pump drive wheel D and then lift off the cover. Fig 26 Loosen screws F and carefully lift up pump hous- ing E.

  • Page 35: Carburettor

    Repair instructions 7.13 Carburettor WARNING! The fuel used for the chain saw has the following characteristics: 1. The liquid and its fumes are poi- sonous. 2. Can cause skin irritation. 3. Is very fl ammable. Description The images for this description do not correspond to the carburettor on the chain saw.
  • Page 36 Repair instructions Function The carburettor functions differently in the following modes: Cold start mode In cold start mode the choke valve (D) is com- pletely shut. This increases the vacuum in the carburettor and fuel is easier to suck from all the diffuser jets (E, F and G).
  • Page 37 Repair instructions Dismantling the carburettor Loosen the choke. Fig 37 Lift out the carburettor with a pair of fl at nosed pli- ers. Fig 38 Pull the throttle actuator rod to the right with a screwdriver. Rotate the carburettor downwards half a revolution.
  • Page 38 Repair instructions Dismantle the pump cover Q and carefully remove the membrane N with gasket P. Unscrew screws A and lift off cover B and carefully remove gasket D and control diaphragm C. Unscrew screw J and remove needle valve G with lever arm F, shaft E and spring H.
  • Page 39 Repair instructions Cleaning and checking 5. That the tips of the high L and low K speed Clean all units in clean petrol. needles are not damaged (see fi gure 41). 6. That the inlet tube R is intact (see fi gure 41). Use compressed air to dry the petrol on the com- ponents.
  • Page 40 Repair instructions Assembly Observe cleanliness when assembling the car- burettor. The slightest contamination can cause malfunctions. 1. If throttle and choke valves with shafts, lever arms and springs are removed, these shall be assembled. The springs are tightened 1-2 revolutions. Lubricate the shaft bearings using a light oil.
  • Page 41 Repair instructions Pressure testing the carburettor Pressure testing should be carried out with the car- burettor fully assembled. The test shall always be done after the carburettor has been repaired, but can also be carried out as trouble shooting before the carburettor is taken apart.
  • Page 42 Repair instructions Assemble on the saw Insert the throttle actuator rod into the carburettor. Fig 47 Turn the carburettor back half a revolution. Fig 48 Hold the carburettor with a pair of fl at nosed pliers and make sure the nipples are pushed down prop- erly into the inlet- and fuel connections.

  • Page 43: Dismantling The Intake System

    Repair instructions 7.14 Dismantling the intake system Dismantle the: • clutch cover • air fi lter cover • air fi lter • air fi lter holder • handle lock • carburettor Bend loose the plastic covers C with a small screwdriver and loosen screws B (see fi...

  • Page 44: Assembling The Intake System

    Repair instructions 7.15 Assembling the intake system Fit and tighten inlet bellows D. Refi t the yellow cover paper. Press the inlet bellows D together and thread it through the handle part (see fi gure 52). Fit and tighten screws B and snap the plastic cov- ers C into place using a small screwdriver.

  • Page 45: Tank Unit

    Repair instructions 7.16 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 fl ammable. Dismantling Dismantle the air fi lter and starter. Bend the han- dle part upwards and use a pair of fl...

  • Page 46: Vibration Damping System

    Repair instructions 7.18 Vibration damping system Dismantling 1. Dismantle the following parts: • Chain and bar. See the Operator’s Manual. • Airfi lter cover. See the Operator’s Manual. • Tank unit and handle. 2. Dismantle the vibration damping springs on the starter housing using a 4 mm Allen key (see Fig 61 fi...

  • Page 47: Replacing The Fuel Fi Lter

    Repair instructions 7.19 Replacing the fuel fi lter 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 fi lter, the old fuel fi lter must be taken out of the tank unit using special tool 502 50 83-01.

  • Page 48: Dismantling The Piston And Cylinder

    Repair instructions 7.22 Dismantling the piston and cylinder Dismantle: • clutch cover (see “Dismantling the clutch cover”) • starter (see “Dismantling the starter”) • handle cover (see “Dismantling the handle part”) Dismantle the stop button and loosen the cables. Remove the air fi lter and air fi lter cover. Disman- tle the carburettor, clutch, muffl...
  • Page 49 Repair instructions Push in the impulse hose as shown in fi gure before removing the cylinder. Fig 72 Screw apart the crankcase half and the cylinder. Fig 73 Carefully pull out piston and crankshaft. Cover with paper over the cylinder opening to prevent dirt from coming in.
  • Page 50 Repair instructions Cleaning and checking Clean all parts, scrape off all gasket residue and carbon from the following places: • The piston crown • Top of the cylinder bore (inside) • The cylinder exhaust port • The base of the cylinder and/or crankcase (see fi...

  • Page 51: Assembling The Piston And Cylinder

    Repair instructions 7.23 Assembling the piston and cylinder Cover the gudgeon pin bearing P with a thin layer of two-stroke oil and insert it into the connecting rod, press in the covers N. (see fi gure 80). Replace the piston with the arrow facing the ex- haust port S (see fi...

  • Page 52: Dismantling The Crankcase And Crankshaft

    Repair instructions 7.24 Dismantling the crankcase and crankshaft See chapter “Dismantling the piston and cylinder”. 7.25 Replacing the crankshaft bearing Remove: • the crankshaft completely from the crankcase. Pull out the crankshaft bearing from the crankshaft (see fi gure 84). Fig 84 Fit the new bearing on the crankshaft using tool 502 50 30-18 (see fi...

  • Page 53: Trouble Shooting

    Trouble shooting 8 Trouble shooting List of contents Trouble shooting ......................54 Trouble shooting techniques ...................55 English -...
  • Page 54 Trouble shooting 8.1 Trouble shooting The different faults which may occur on the chain saw are divided into four groups. Within each group possible operating faults are listed to the left while the probable fault alternatives are listed to the right. The most likely fault is listed fi...
  • Page 55 Trouble shooting High speed Acceleration and retardation Does not Adjust the L-screw Does not run Adjust the H-screw accelerate Adjust the H-screw at full throttle Blocked air fi lter Blocked air fi lter Tank venting clogged Tank venting clogged The fuel fi lter is clogged The fuel fi...
  • Page 56 505 46 25-26 2008W34...

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