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Husqvarna 545RX Workshop Manual

Husqvarna 545RX Workshop Manual

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Workshop manual
545RX, 545FR, 545FX, 545FXT,
545RX, 545RXT, 345FR


Table of Contents

Summary of Contents for Husqvarna 545RX

  • Page 1 Workshop manual 545RX, 545FR, 545FX, 545FXT, 545RX, 545RXT, 345FR English...
  • Page 3: Table Of Contents

    Starter Workshop Manual Brushcutter, Trimmer 545RX, 545FR, 545FX, 545FXT, 545RX, 545RXT, 345FR Contents General recommendations ___________________ 2 1. Starter _________________________________ 3 2. Electrical system _________________________ 7 3. Fuel system ___________________________ 15 4. Centrifugal clutch _______________________ 31 5. Bevel gear ____________________________ 37 6.
  • Page 4: General Recommendations

    The engine’s exhaust fumes are poisonous. Test run the in the Operator’s Manual. The assembly of other equipment engine outdoors. or accessories or spare parts not approved by Husqvarna can result in the failure to meet these safety demands and that Special tools the person carrying out assembly bears responsibility for this.
  • Page 5: Starter

    Starter Starter Contents Dismantling __________________________________ 4 Assembly ___________________________________ 5 Replacing the drive dogs _______________________ 6...
  • Page 6 Starter WARNING! Protective glasses should be worn when working on the starter to avoid injury to the eyes if, for some reason, the return spring should fl y out. Dismantling Dismantling Remove the starter from the engine. Remove the 4 screws and lift off the star- ter with the attached air guide plate.
  • Page 7 Starter Remove the spring cassette. Remove the two bolts holding the spring cassette and remove the cassette for replacement if necessary. WARNING! Wear protective glasses. The return spring can fl y out and cause personal injury if improperly handled. Assembly Assembly Clean requisite parts and assemble in the Clean all components before assembly:...
  • Page 8 Starter Tighten the return spring. Tighten the return spring. Check the spring tension. Lift up the starter cord when the return spring is completely loose and the cord Press the air guide plate on to the starter pulled out completely. housing.
  • Page 9: Electrical System

    Electrical system Electrical system Contents Checking the ignition spark _____________________ 8 Replacing the spark plug cover _________________ 10 Dismantling ________________________________ 10 Drive dogs _________________________________ 11 Assembly __________________________________ 12 Heated handles _____________________________ 12...
  • Page 10: Checking The Ignition Spark

    Electrical system The engine is equipped with an electronic ignition system completely without moving parts. Conse- quently, 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 inter- preted as weak and can be diffi...
  • Page 11 Electrical system If no spark occurs even now, remove the If no spark occurs even now, remove the short-circuit cable from the stop switch. short-circuit cable from the stop switch. If the plug now sparks, the fault is either in The stop switch can be easily detached the stop switch or the short-circuit cable.
  • Page 12: Replacing The Spark Plug Cover

    Electrical system Adjust the air gap. Adjust the air gap as needed to the correct value. • Loosen the bolts. • Position the feeler gauge and press the ignition module against the fl ywheel. • Tighten the bolts and check the air gap again.
  • Page 13: Drive Dogs

    Electrical system Remove the nut holding the fl ywheel. Remove the nut holding the fl ywheel. Remove the fl ywheel. Remove the fl ywheel from the crankshaft using punch no. 502 51 94-01. Remove any generator. Leave a gap of approx. 2 mm between the punch and the fl...
  • Page 14: Assembly

    Electrical system Replace damaged parts. Replace damaged parts. Assemble in the reverse order. Assemble in the reverse order. Ensure that the recoil springs are in the correct position. Check that the hooks can be turned freely when the bolts are tight. 502 50 18-01 Assembly Assembly...
  • Page 15 Electrical system Separate the contacts (A-A) and (B-B). Separate the contacts (A-A) and (B-B). Then extend the cables (A) and (B) with Then extend the cables (A) and (B) with approx. 90 cm long steel wires attached to approx. 90 cm long steel wires attached to the contacts.
  • Page 16 Electrical system...
  • Page 17: Fuel System

    Fuel system Fuel system Contents Air fi lter ___________________________________ 16 Tank venting _______________________________ 16 Fuel fi lter __________________________________ 17 Carburettor ________________________________ 18 Assembly __________________________________ 24 Carburettor settings __________________________ 25 Thumb throttle _____________________________ 27 Index fi nger throttle __________________________ 28 Trouble Shooting Guide ______________________ 30...
  • Page 18: Air Fi Lter

    Fuel system In addition to the fuel tank and carburettor, the fuel system consists of the air fi lter, fuel fi lter and tank venting. All these components interact so that the engine receives the optimal mixture of fuel and air to make it as effi...
  • Page 19: Fuel Fi Lter

    Fuel system Check that the tank venting valve works Tank venting takes place through the fuel correctly. cap and needs to be functional for the engine to work. Replace the fuel cap if the valve is faulty. • Remove the cover over the fuel pump and the fuel hose from the carburettor.
  • Page 20: Carburettor

    Fuel system Carburettor Carburettor Dismantling Dismantling Remove the cylinder cover, the air fi lter Remove the cylinder cover, the air fi lter cover, the air fi lter and the small cover (B). cover and the air fi lter. Remove the hoses (C and D). Remove the 4 screws (A) and lift off the cover (B).
  • Page 21 Fuel system The blending unit The blending unit Fuel and air are mixed here. In this section of the carburettor fuel and air are mixed in the proper proportions. The choke and throttle valves are placed here. In the middle of the venturi (narrowest part of the throughput) the main jet (D) is found.
  • Page 22 Fuel system Pressure test the metering unit. Connect pressure tester 531 03 06-23 to the fuel hose nipple. Lower the carburettor in a vessel with petrol in order to discover any leaks more easily. Test the pressure at 50 kPa (0,5 bar). No leakage is permitted.
  • Page 23 Fuel system Remove the pump diaphragm. Remove the bolt holding the cover over the pump diaphragm. Check the diaphragm for damage. Lift off the cover (A), the gasket (B) and Remove the fuel screen and clean it or the diaphragm (C). attach a new one.
  • Page 24 Fuel system Check valves and dampers for wear. Remove the valves and dampers. If these components are worn, idling is disrupted. Replace if required. Always replace the valves and dampers at the same time. Assembling the carburettor Assembling the carburettor Blow the carburettor housing clean.
  • Page 25 Fuel system • Mount the valves and dampers. Tip! Any numbers on the valves should be able to be read from the outside. Replace the fuel screen (A) if damaged or if it cannot be cleaned. Place the pump diaphragm (B) closest to the carburettor housing.
  • Page 26: Assembly

    Fuel system Check that the carburettor is sealed. Connect pressure tester 531 03 06-23 to the fuel intake on the carburettor. No leakage is permitted at 50 kPa. Pump up the pressure to 50 kPa. Lower the carburettor in a vessel with petrol in order to discover any leaks more easily.
  • Page 27: Carburettor Settings

    Fuel system Fit the carburettor cover to the carburettor. 4. Insert the 4 screws (A) in the carburet- tor cover. Check that the choke and the throttle valves are working. 5. Check that the choke valve in the car- burettor and the choke control in the cover are both open.
  • Page 28 Fuel system Basic setting The carburettor is set to its basic setting when test run at the factory. The basic setting is “richer” than the optimal setting (fast idle speed is 600–800 rpm under the recommend- ed max. speed) and should be kept during the engine’s fi rst working hours. Thereafter the carburettor should be fi...
  • Page 29: Thumb Throttle

    Fuel system Setting the L jet Setting the H jet 1. Fit the trimmer head T45 and use 2.7 mm plain cord. The 1. Fit the trimmer head T45 and use 2.7 mm plain cord. The cord length should be as standard, i.e. reach the knife on the cord length should be as standard, i.e.
  • Page 30: Index Fi Nger Throttle

    Fuel system Check for wear on pins (A) and (B). Replace the throttle control (C) and lever arm (D) if necessary. Check that the cables are properly pressed into the cut-outs (E) and that the throttle cable (F) is in the right groove. If necessary, attach it with silicon adhesive in order to facilitate assembly.
  • Page 31 Fuel system Dismantle the throttle handle (A), the lock to prevent accidental throttle operation (B), the start throttle lock (C) and the th- rottle stop (D) in order to check if replace- ment is necessary. The stop switch can also be disassem- bled now, and replaced if necessary.
  • Page 32: Trouble Shooting Guide

    Fuel system Trouble Shooting Guide Symptom Starting Low speed Acceleration/ Deceleration Probable causes ● ● ● ● Stop screw for the throttle not working ● ● ● ● ● ● ● Fuel tank/hose Fuel fi lter blocked ● ● ● ●...
  • Page 33: Centrifugal Clutch

    Centrifugal clutch Centrifugal clutch Contents Dismantling ________________________________ 32 Assembly _________________________________ 34 Clutch drum Dismantling _____________________________ 34 Assembly _______________________________ 36...
  • Page 34: Dismantling

    Centrifugal clutch The centrifugal clutch has the task of transferring the power from the engine to the cutting equip- ment’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.
  • Page 35 Centrifugal clutch Remove the vibration dampers. Remove the vibration dampers. Remove the 4 screws holding the clutch Remove the 4 screws holding the clutch cover and lift the engine body to the side. cover on the engine. Lift the engine body to the side so that the clutch becomes accessible.
  • Page 36: Assembly

    Centrifugal clutch Clean and inspect the different parts with Clean and inspect the different parts with regard to wear or other damage. regard to wear or other damage. Wear on the clutch shoes must not be greater than shown in the illustration. Check the play in the sleeve bearings in the clutch shoes and the wear on the springs by the fastening hooks.
  • Page 37 Centrifugal clutch Remove the clutch drum from the drive Remove the clutch drum from the drive axle axle. The drum is tightly screwed to the drive axle. Hold the drive axle in a vice and unscrew the clutch drum using the 502 52 16-02 tool.
  • Page 38: Assembly

    Centrifugal clutch Assembly Assembly 1. Heat the clutch housing to approx. 110 Assemble the bearing in the clutch hou- °C using a hot air gun. sing. 2. Insert the bearing into position in the clutch housing and fi t the circlip (G). 3.
  • Page 39: Bevel Gear

    Angle gear Angle gear Contents Dismantling ________________________________ 38 Assembly __________________________________ 39 Shaft _____________________________________ 40...
  • Page 40 Angle 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 requires to work effi ciently. Second, the angle gear contributes to the saw operator’s working stance so that it is comfortable and at the same time effi...
  • Page 41 Angle gear Remove the lubricant top-up plug. Remove the lubricant top-up plug and warm the entire gearbox using a hot air Warm the gearbox and knock it against a gun to about 150°C. wooden block so that the input axle falls out.
  • Page 42 Angle gear Shaft Shaft Prise off the plastic sleeve and the O-ring. Prise away the plastic sleeve (A) and the O-ring (B) using a knife. When fi tting, a new O-ring must be used. When fi tting, a new O-ring must be used. Place the plastic sleeve in position in the To avoid damage from the sharp edges of gear housing and slide the O-ring on to...
  • Page 43: Cylinder And Piston

    Cylinder and piston Cylinder and piston Contents Dismantling ________________________________ 42 Decompression valve ________________________ 43 Cleaning, inspection _________________________ 43 Assembly _________________________________ 44 Analysis and actions _________________________ 45 Service tips ________________________________ 49 Wear tolerances ____________________________ 49...
  • Page 44: Dismantling

    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.
  • Page 45: Decompression Valve

    Cylinder and piston Dismantle the piston. Push the gudgeon pin from the piston us- ing punch 505 38 17-05. If the pin is too tight, carefully warm the piston. 505 38 17-05 Decompression valve Decompression valve Clean the decompression valve and Clean the decompression valve using a check that the valve head is not damaged wire brush.
  • Page 46: Assembly

    Cylinder and piston Assembly Assembly Lubricate the gudgeon pin’s needle bear- Lubricate the gudgeon pin’s needle bear- ing with a few drops of engine oil. ing with a few drops of engine oil and fi t Direct the arrow on the top of the piston the piston.
  • Page 47: Analysis And Actions

    Blocked spark arrestor mesh in Clean or replace the spark arrestor mesh. the muffl er. 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.
  • Page 48 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 combustion gases that are blown past the piston. This type of piston damage starts at the exhaust port where carbon deposits can be- come loose and get trapped between the piston and the cylinder wall.
  • Page 49 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.
  • Page 50 Cylinder and piston Cause: Action: • Faulty air fi lter. Small dust particles Fit a fi ner grade fi lter. pass through the fi lter. • The fi lter is worn out due to too Check the fi lter carefully for holes and much cleaning, whereby small holes damage after cleaning.
  • Page 51: Service Tips

    Cylinder and piston Service tips Defect: Action: In severe cases – replace the cylinder. Broken cooling fi ns, damaged threads or sheared bolts by Repair the threads using Heli-Coil. the exhaust port. Seizure marks in the cylinder bore (especially by the ex- Polish the damaged area using a fi...
  • Page 52 Cylinder and piston...
  • Page 53: Crankshaft And Crankcase

    Crankshaft and crankcase Crankshaft and crankcase Contents Dismantling ________________________________ 52 Inspecting the crankshaft ______________________ 53 Assembly _________________________________ 54...
  • Page 54 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 con- necting rod is exposed to large acceleration and retardation forces as it moves between the top and bottom dead centres.
  • Page 55 Crankshaft and crankcase Separate the crankcase halves from Separate the crankcase halves from each each other. other.. Prise off the guide rail from the fl ywheel This can be done without tools as the side of the crankcase half. crankshaft has a sliding fi t in the bearing seatings.
  • Page 56 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. The connecting Check the crank bearing.
  • Page 57 Crankshaft and crankcase Placera vevaxeln, överströmningska- Fit the crankshaft and the guide rail for nalernas ledskena samt packningen på the bypass channels to the clutch side of kopplingssidans vevhushalva. the crankcase half. Put the crankcase gasket in place and make sure that both guide pins are in position.
  • Page 58 Crankshaft and crankcase...
  • Page 59: Tools

    List of tools Tools Contents Starter ____________________________________ 58 Electrical system ____________________________ 58 Fuel system ________________________________ 58 Centrifugal clutch ____________________________ 58 Angle gear _________________________________ 59 Cylinder and piston __________________________ 59 Crankshaft and crankcase _____________________ 59 Workshop equipment _________________________ 59...
  • Page 60 List of tools 502 71 13-01 505 69 85-70 530 03 55-60 502 50 18-01 502 21 58-01 502 51 34-02 502 71 14-01 521 54 83-01 531 03 06-23 502 50 06-01 502 50 18-01 502 52 16-02 521 54 83-01 501 60 02-03 502 50 18-01 502 50 83-01...
  • Page 61 List of tools 502 50 65-01 502 50 18-01 505 38 17-09 502 51 03-01 544 13 05-01 502 50 18-01 503 97 64-01 505 38 17-05 531 03 06-23 544 13 08-01 544 13 09-01 503 80 17-01 502 50 70-01 502 71 14-01 502 54 11-01 505 69 85-70...
  • Page 62 List of tools...
  • Page 63: Technical Data

    Technical Data Technical Data Contents Engine ____________________________________ 62 Ignition system ______________________________ 62 Carburettor ________________________________ 62 Clutch ____________________________________ 62 Driving ____________________________________ 62 Dimensions ________________________________ 62...
  • Page 64 Technical Data 545FX 545FXT 545RX 545RXT Engine Displacement, cm 45.7 45.7 45.7 45.7 Cylinder bore, mm Stroke, mm Compression ratio Max output, kW/speed, rpmin 2,2/9.000 2,2/9.000 2,1/9.000 2,1/9.000 Decompression valve Blade shaft speed, rpm 10.100 10.100 8.800 8.800 Catalytic converter kit...
  • Page 66 115 48 40-26 2012W12...

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