1.5 Servicing tools The manual gives information about necessary servicing tools. Always use original tools from Husqvarna. 1719 - 002 - 19.04.2023 Introduction - 3...
2 Safety 2.1 Safety definitions • Wear protective gloves when you replace the crankshaft bearings. The crankcase halves are hot, Warnings, cautions and notes are used to point out risk of burn injuries. specially important parts of the manual. • Make sure that the chain brake is engaged when you remove the pressure spring on the chain brake.
Noise emission to the environment label as per European Directive 2000/14/EC, UK directives and regulations and New South Wales legislation "Protection of the Environment Operations (Noise Control) Regulation 2017". The guaranteed sound power level of the product is specified in Technical data on page 49 and on the label.
3 Prepare and do servicing on the product 3.1 Maintenance schedule Maintenance Before After 100 After 40 h operation Clean the external surfaces. After each operation. Clean the muffler, exhaust pipe and engine from dirt and unwanted lubricant. After each operation. Make sure that the saw chain does not move at idle speed.
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Item Description Article num- Piston stop To lock the crankshaft. 521 54 83-01 Fuel filter hook To pull out the fuel filter from the tank. 502 50 83-01 Mandrel To remove the flywheel. 502 51 94-01 HSH Interface Box Kit To do a check of the product and install updates to the firm- 598 07 28-02 ware.
For best results and performance use Husqvarna two- stroke oil. If Husqvarna two-stroke oil is not available, use a two- stroke oil of good quality for aircooled engines. Speak to your servicing dealer to select the correct oil. 6.2.2.3 To mix gasoline and two-stroke oil...
7 Repair instructions 7.1 Product overview 1. Air filter cover 15. Chain oil tank 2. Spark plug 16. Muffler 3. Spark plug cap 17. Chain brake and front hand guard 4. Air filter 18. Front handle 5. Vibration element 19. Right hand guard 6.
7.3 To connect the product to the Husqvarna Service Hub (HSH) Note: It can be necessary to install firmware to a new spare part. Make sure that you know the Husqvarna Identification Number (HID) of the new spare parts before you connect the product to the Husqvarna Service Hub (HSH).
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7.4.2 To install the front handguard 7.4.3 To disassemble and assemble the chain brake 1. Push the lever and install the front handguard. WARNING: Make sure that the chain brake spring does not eject and cause injury. Use protective goggles. 1.
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4. Remove the 4 screws and the chain brake cover. 7. Remove the shain brake assembly. 5. Remove the chain brake spring. 7.4.4 To clean and examine the chain brake a) Hold one hand on the chain brake spring. Push a 1.
7.5.2 To replace the spiked bumper WARNING: The engine must be off. 1. Remove the clutch cover. 2. Remove the 2 screws, the chain catcher and the 2. Release the front handle. The guide bar tip falls onto spiked bumper. the stump.
7.6 Muffler 4. Remove the screw and pull out the spark arrester screen. 7.6.1 To remove and install the muffler WARNING: Do not touch a hot muffler. Risk of burn injuries. 1. Remove the clutch cover. 5. Install in the opposite sequence. 7.6.2 To clean and examine the muffler 1.
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3. Install the opposite sequence. 4. Remove the throttle wire from the throttle trigger. CAUTION: Use a threadlocker when you install the 3 screws. 7.7.2 To disassemble and assemble the rear handle 1. Remove the screw and the handle cover. 5.
4. Remove the throttle wire from the tank unit. 3. Pull out the starter rope approximately 30 cm/12 in and put it in the notch on the pulley. 4. Let the pulley rotate slowly rearward to release the 5. Install in the opposite sequence. recoil spring.
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• Lubricate the starter pawls on the starter unit. 10. Push down the knot into position in the spring guide (B). • Lubricate the starter spring. 1 cm/0.5 in 7.8.3 To replace a broken or worn starter rope 1. Remove the starter rope from the starter unit. Refer To disassemble the starter unit on page 19 .
Only use spark spark plug. plugs recommended by Husqvarna, refer to the WARNING: To prevent the risk of fire, do operator's manual. not hold the spark plug near the spark plug hole.
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7.9.4 To remove the ignition module 11. Remove the 3 screws and the 2 covers for the ignition cable. 1. Remove the clutch cover. 2. Remove the starter unit (A). 3. Loosen the ignition cord (B) from the air conductor (C).
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7.9.5 To install the ignition module 3. Put a air gap gauge between the ignition module and the flywheel. Tighten the screw to the correct 1. Install the the ignition cable. Make sure that the Servicing tools on page 9 . torque.
11. Install the starter unit and the air conductor. Refer to 10. Remove the flywheel nut. To remove the flywheel on page 24 . 12. Install the clutch cover. 7.10 Flywheel 7.10.1 To remove the flywheel 1. Remove the starter unit (A). 11.
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7.10.2 To install the flywheel 6. Make sure that you install the springs in the correct position, as shown in the illustration. 1. Clean the crankshaft. 2. Put the flywheel on the crankshaft. Turn the flywheel until the key goes into the key slot on the shaft. 3.
7.11 Centrifugal clutch 11. Install in the opposite sequence. 7.11.2 To clean and examine the centrifugal clutch 7.11.1 To remove and install the centrifugal clutch 1. Measure the diameter of the clutch shoes across the 1. Disengage the chain brake. full clutch hub.
4. Lubricate the needle bearing with a grease gun. Use 5. Remove 4 screws, the chain guide plate (A), the engine oil or a bearing grease of high quality. muffler cover (B) and the cover for the pump housing (C). 6.
7.12.2 To disassemble and examine the lubrication b) Turn the adjustment screw counterclockwise to increase the chain oil flow. system To remove 1. Remove the lubrication system. Refer to and install the lubrication system on page 27 . 2. Remove the pin (A), the adjustment screw (B) and the spring (C).
Device. ® 7.14.1 To install the Husqvarna Connectivity Device ® Do the steps that follow to install the Husqvarna Connectivity Device. For more information about ® the Husqvarna Connectivity Device, refer to www.husqvarna.com. 1. Remove the screw and open the plastic cover.
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4. Remove the screw that hold the start/stop switch 8. Remove the connector from the holder. (A). 9. Remove the carburetor and the start/stop switch. 5. Remove the start/stop switch from the choke shaft (B). 6. Remove the 2 screws on the carburetor. 10.
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11. Disconnect the connectors on the carburetor. 3. Remove the 4 screws (A) and the 4 washers (B). 12. Remove the suction hose from the carburetor. 13. Install in the opposite sequence. 7.15.2 To disassemble the carburetor 4. Remove the metering cover (C) and the 2 gaskets To remove and 1.
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8. Remove the screw (R) and the throttle plate (S). 7.15.3 To clean and examine the carburetor 1. Clean all parts in clean gasoline. Use compressed air to dry the gasoline. Point the air through all channels in the carburetor housing and make sure that the channels are not blocked.
3. Connect the pressure tester to the fuel inlet on the 3. Remove the fuel hoses (A) from the air purge bulb. carburetor. Increase the pressure to 50kPa. Refer to Servicing tools on page 9 . 4. Remove the screw (B). 5.
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To remove and 3. Remove the front handle. Refer to 10. Remove the tank unit. install the front handle on page 17 . 4. Remove the air filter cover. 5. Remove the air filter. To remove and 6. Remove the carburetor. Refer to install the carburetor on page 29 .
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5. Install in the opposite sequence. 7.17.6 Air pressure in the fuel tank The two-way tank valve has a controlled opening pressure in the two directions. The controlled opening prevents positive pressure or vacuum in the fuel tank, and fuel leakage. Positive pressure, vacuum and fuel leakage decreases engine performance.
7.18 Vibration damping system 7.19 Cylinder and piston 7.18.1 To disassemble and assemble the vibration 7.19.1 To remove the cylinder and piston damping system To disassemble 1. Remove the starter unit. Refer to the starter unit on page 19 . 1.
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8. Remove the 2 screws and the cover for the ignition 12. Remove the 2 screws. cable. 13. Remove the cylinder cover. 9. Remove the 2 screws and the ignition module. To remove and install 14. Remove the muffler. Refer to the muffler on page 17 .
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16. Put a cover on the crankcase opening. 7.19.2 To clean the cylinder and piston 1. Clean the piston crown. 17. Use pointed pliers to remove the snap ring (A). Keep your thumb on the snap ring to make sure that it 2.
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7.19.5 To examine the piston rings 1. Examine the piston rings for damage. 2. Replace damaged piston rings. 7.19.6 Piston damages Score marks on the piston Incorrect carburetor setting. Too high speed. Too low octane fuel. The fuel has a too low octane grade. Carbon build-up Incorrect carburetor setting.
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7.19.7 To install the cylinder and piston 8. Put a new cylinder base gasket on the crankcase. 1. Put a cover on the crankcase opening. 2. Lubricate the needle bearing (A) and put it into the connecting rod. Make sure the bearing moves freely in the connecting rod.
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13. Install the cylinder cover. 16. Install the cover for the ignition cable. 14. Install the 2 screws. 17. Install the spark plug. 18. Connect the spark plug cap to the spark plug. 19. Install the inlet pipe and make sure that the inlet plate (H) is in the correct position.
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Servicing 21. Push the inlet pipe through the carburetor bracket to 5. Attach the spark plug adapter (A). Refer to tools on page 9 . install the carburetor bracket. To remove and install 22. Install the tank unit. Refer to the tank unit on page 33 .
10. Increase the pressure to 0.8 bar. Wait for 30 Note: Make sure that no dirt or object can come into seconds. Make sure the pressure does no decrease the bearings. to less than 0.6 bar. Remove the covers from the muffler and the carburetor, tighten the bolts to the 7.20.2 To disassemble the crankcase correct torque.
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6. Remove the 2 crankcase bearings. Refer to 3. Make sure that the bearing surfaces in the small Servicing tools on page 9 . end of the connecting rod are not worn or have discoloration. 4. Make sure that the crankpin bearing is attached correctly and does not have radial play.
a) On the clutch side. 4. Attach the gasket (A) to one of the crankcase half on the clutch side. b) On the flywheel side. 5. Put a crankshaft cap (B) on the flywheel side of the Servicing tools on page 9 . crankshaft.
5. Remove the guide bar bolt from the oil tank. 5. Put 2 spacers on the guide bar bolt. 6. Attach a nut to the guide bar bolt and tighten the 7.21.2 To install the guide bar bolt nut until the guide bar bolt is tightly attached to the crankcase.
8 Troubleshooting 8.1 Troubleshooting Symptom Possible causes Recommended step The product does not start. The air filter is dirty. Clean or replace the air filter. The choke is damaged or worn. Repair or replace the choke. Leakage or dirt in the fuel hose. Clean the or replace fuel hose.
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Symptom Possible causes Recommended step The engine rpm don not increase at The air filter is dirty. The air filter is dirty. full throttle. The tank valve is damaged. Replace the tank valve. Leakage or dirt in the fuel hose. Clean the or replace fuel hose.
9 Technical data 9.1 Technical data 540XP Mark III Engine Cylinder displacement, cm 39.1 Cylinder bore, Ø mm Stroke length, mm 31.1 Idle speed, rpm 3000 Maximum engine power acc. to ISO 7293, kW/hp @ rpm 1.9/2.6 @ 10500 Ignition system...
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