Husqvarna 122C Workshop Manual
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Workshop manual
122C 122LD
English

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Table of Contents
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Summary of Contents for Husqvarna 122C

  • Page 1 Workshop manual 122C 122LD English...
  • Page 3: Table Of Contents

    Starter Workshop Manual Brushcutter, Trimmer Model 122C, 122LD Contents General recommendations ___________________ 2 1. Starter _________________________________ 3 2. Electrical system ________________________ 7 3. Fuel system ___________________________ 15 4. Centrifugal clutch _______________________ 27 5. Bevel gear ____________________________ 31 6. Cylinder and piston ______________________ 35 7.
  • Page 4: General Recommendations

    Operator’s Manual. The assembly of other equipment or ac- The engine’s exhaust fumes are poisonous. Test run the engine cessories or spare parts not approved by Husqvarna can result outdoors. in the failure to meet these safety demands and that 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 Dismantling Dismantling Remove the 8 screws and lift off the starter Starter, cylinder cover and half of the cover from the engine body. over the muffl er is one unit. Remove all 8 screws including those holding the guard screen over the muffl...
  • Page 7 Starter Assembly Assembly Clean the component parts and assemble in Clean component parts before assembling. the reverse order as set out for dismantling. Replace the return spring/starter pulley and starter cord, if necessary. NOTE! The return spring and starter pulley are supplied pre-assembled and are fi...
  • Page 8 Starter Tension the return spring. Tension the return spring. Check the spring tension. Pull the starter cord out completely and slow the starter pulley with your thumb. Fit the starter on the engine body. Lift the cord into the notch on the starter pulley.
  • Page 9: Electrical System

    Electrical system Electrical system Contents Checking the ignition spark ______________________ 8 Dismantling __________________________________ 10 Assembly ___________________________________ 12...
  • Page 10 Electrical system The engine is equipped with an electronic ignition system completely without moving parts. Consequently, 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 interpreted as weak and can be diffi...
  • Page 11 Electrical system When no spark is obtained, dismantle If there is still no spark, remove the short- the short-circuit cable from the ignition circuit cable from the short-circuit switch. switch. Prise up the switch by inserting a small Still no spark? screwdriver or knife into the short end of the ignition switch.
  • Page 12 Electrical system Still no spark? Still no spark? Check other cables and connections for Check other cables and connections. poor contacts (dirt, corrosion, cable brea- kage and damaged insulation). Make sure that the cables are correctly drawn and lie in the cable grooves. Do not forget to check the cables in the throttle too.
  • Page 13 Electrical system Separate the short-circuit cables. Separate both short-circuit cables. Remove the screws (A) and slide the Remove both screws (A), one on each throttle forwards. side of the throttle handle. Push the throttle forward onto the shaft. Loosen the screws and remove the shaft Loosen the screws and remove the shaft from the engine.
  • Page 14 Electrical system Dismantle the centrifugal clutch. Remove the two screws holding the cen- trifugal clutch. Lift off the clutch and both support wash- ers. 502 71 27-02 Fit the piston stop no. 502 54 15-01 and Fit piston stop no. 502 54 15-01 in the remove the nut holding the fl...
  • Page 15 Electrical system Assemble the ignition module and adjust Assemble the ignition module. the air gap to 0.3 mm. Adjust the air gap. It should be 0.3 mm between the permanent magnets in the fl ywheel and the ignition module. Assemble other parts in the reverse order as set out for dismantling.
  • Page 16 Electrical system...
  • Page 17: Fuel System

    Fuel system Fuel system Contents Air fi lter ____________________________________ 16 Tank venting ________________________________ 16 Fuel fi lter ___________________________________ 17 Fuel pump __________________________________ 17 Carburettor _________________________________ 17 Dismantling the carburettor ____________________ 19 Assembling the carburettor _____________________ 21 Throttle ____________________________________ 23 Carburettor settings __________________________ 24 Trouble shooting guide ________________________ 26...
  • Page 18: Air Fi Lter

    Ensure that the fi lter is dry before refi tting it. TIP! Use Husqvarna’s cleaning agent Active Cleaning no. 505 69 85-70. Impregnate the fi lter with air fi lter oil. Impregnate the fi lter with air fi lter oil.
  • Page 19: Fuel Fi Lter

    Fuel system Check that the slot in the non-return valve Remove the fi lter housing (A) from the (B) is not damaged. bracket (D) on the carburettor cover using fl at nose pliers. Clean the foamed plastic fi lter (C). Remove the fi...
  • Page 20 Fuel system The carburettor’s design The carburettor’s design The carburettor can be divided into three The carburettor can be divided into three different functional units: the metering different functional units: the metering unit, the blending unit, and the pump unit. unit, the blending unit, and the pump unit.
  • Page 21: Dismantling The Carburettor

    Fuel system Dismantling the Dismantling the carburettor carburettor The metering unit The metering unit Remove the 4 screws (A) and lift off the Remove the 4 screws (A) and pull apart cover (B) and the pump bellows (C). the various parts for inspection and pos- sible replacement.
  • Page 22 Fuel system Check the needle valve and the lever arm Check the needle valve for damage on the tip and in the lever arm groove. for damage or wear. Check the lever arm for damage to the Replace damaged components with new ones.
  • Page 23: Assembling The Carburettor

    Fuel system The blending unit The blending unit Remove the main jet. Press out the main jet (A) with a suitable punch. Remember how far it is pressed into the carburettor housing. Check valves and dampers for wear. Remove the valves and dampers. If these components are worn, idling is disrupted.
  • Page 24 Fuel system Fit the carburettor needles and adjust Fit the carburettor needles. them to the basic setting: Screw them in so that they just reach the bottom of the needle seat. H = 1.0 turn L = 1.5 turns Then screw them out according to the basic setting: H = 1.0 turn L = 1.5 turns...
  • Page 25: Throttle

    Fuel system Assembly Assembly Connect the fuel hoses to the carburettor 1. Connect the fuel hoses to the carburet- and screw it on to the distance piece. tor. Do not forget the top screw! 2 Hold the carburettor against the air fi...
  • Page 26: Carburettor Settings

    Fuel system Carburettor settings WARNING! When testing the engine in connection with carburettor adjustment, the clutch and clutch cover must be mounted together with the shaft and angle gear under all circumstances Otherwise there is a risk of the clutch becoming loose resulting in serious personal injury.
  • Page 27 Fuel system Fine adjustment NOTE! Fine adjustment of the carburettor should be carried out after If the cutting equipment rotates while idling, the T-screw the engine has been “run-in”. It is important that the air fi lter is must be turned anticlockwise until it stops rotating. clean and that the carburettor cover is fi...
  • Page 28: 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 29: Centrifugal Clutch

    Centrifugal clutch Centrifugal clutch Contents Dismantling __________________________________ 28 Assembly __________________________________ 28 Replacing the clutch drum _____________________ 29...
  • Page 30 Centrifugal clutch The centrifugal clutch has the task of transferring the power from the engine to the cutting equipment’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 31 Centrifugal clutch Replacing the clutch Replacing the clutch drum drum Pull both short-circuit cables apart and Pull the short-circuit cables apart and disconnect the throttle cable from the disconnect the throttle cable from the carburettor. carburettor. Remove both screws (A), one on each Remove the screws (A) and slide the side of the throttle handle.
  • Page 32 Centrifugal clutch...
  • Page 33: Bevel Gear

    Bevel gear Bevel gear Contents Dismantling _________________________________ 32 Assembly __________________________________ 33...
  • Page 34 Bevel 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 re- quires to work effi ciently. Secondly, the angle gear contributes towards the operator’s working stance so that it is comfortable and at the same time effi...
  • Page 35 Bevel gear Dismantle the bearings from the output Dismantle the bearings from the output and input axles. and input axles with the help of a small bearing puller. TIP! Hold the bearing puller in a vice so that it gains a better grip around the bearing. Assembly Clean all component parts and replace if damaged or worn.
  • Page 36 Bevel gear...
  • Page 37: Cylinder And Piston

    Cylinder and piston Cylinder and piston Contents Dismantling ________________________________ 36 Cleaning, inspection _________________________ 37 Analysis and actions _________________________ 38 Service tips ________________________________ 42 Wear tolerances ____________________________ 43 Assembly _________________________________ 43...
  • Page 38: 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 39: Cleaning, Inspection

    Cylinder and piston Dismantle the piston. Push the gudgeon pin from the piston using punch 502 52 42-01. If the pin is too tight, carefully warm the piston. NOTE! Make sure the spacer washers on each side of the needle bearing are not misplaced.
  • Page 40: Analysis And Actions

    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. Mixing ratio: 1:33 (3%) or 1:25 (4%).
  • Page 41 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 combus- tion gases that are blown past the piston. This type of piston damage starts at the exhaust port where carbon deposits can become loose and get trapped between the piston and the cylinder wall.
  • Page 42 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 43 Cylinder and piston Cause: Action: • Faulty air fi lter. Small dust particles Fit a fi ner grade fi lter. pass through the fi lter. Check the fi lter carefully for holes and • The fi lter is worn out due to too damage after cleaning.
  • Page 44: Service Tips

    Cylinder and piston Larger, harder particles that enter the engine cause serious damage to the under- side of the piston skirt. Cause: Action: • Air fi lter damaged or missing. Fit a new air fi lter. Regular service and inspection. •...
  • Page 45: Wear Tolerances

    Cylinder and piston Wear tolerances Piston ring gap Piston ring groove Piston ring play Cylinder bore When the surface coating is Max. 1.0 mm with the piston Max. 1.6 mm. Clean the groove Max. 0.15 mm. Clean the groove worn and aluminium appears. ring inserted in the lower part of before checking the measure- before checking the measure-...
  • Page 46 Cylinder and piston Check the carburettor’s distance piece/ heat shield (A) for cracks. Make sure the impulse channel (B) is open and that the gasket (C) is not dam- aged. Screw the distance piece to the cylinder and tighten the screws crosswise and diagonally.
  • Page 47: Crankshaft And Crankcase

    Crankshaft and crankcase Crankshaft and crankcase Contents Dismantling ________________________________ 46 Inspecting the crankshaft ______________________ 47 Assembly _________________________________ 48...
  • Page 48 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 connecting rod is exposed to large acceleration and retardation forces as it moves bet- ween the top and bottom dead centres.
  • Page 49 Crankshaft and crankcase Dismantle the ball-bearings from the Dismantle the ball-bearings from the crankcase halves. crankcase halves. Heat the crankcase halves to 110°C using a hot air gun. Knock the crankcase half against a Knock the crankcase half against a wooden block so that the ball-bearing wooden block so that the ball-bearing falls out.
  • Page 50 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. Check the crank bearing. The connecting rod shall not have any radial play (up and down).
  • Page 51 Crankshaft and crankcase Fit the crankshaft in the clutch side’s Fit the crankshaft in the clutch side’s crankcase half. crankcase half. Lubricate the stub axle with a few drops of oil and carefully slide in the crankshaft in the ball-bearing so that the sealing ring is not damaged by the shoulder on the stub axle.
  • Page 52 Crankshaft and crankcase Full engine assembly sequence 1. Crankshaft with attached piston in the crankcase. 2. Flywheel on the crankshaft. 3. Drive cup on the crankshaft. 4. Centrifugal clutch on the fl ywheel. 5. Cylinder. 6. Ignition module, air gap adjustment. 502 51 34-02 7.
  • Page 53: Tools

    List of tools Tools Contents Starter __________________________________ 52 Electrical system __________________________ 52 Fuel system ______________________________ 52 Centrifugal clutch __________________________ 52 Bevel gear _______________________________ 53 Cylinder and piston ________________________ 53 Crankshaft and crankcase ___________________ 53 Workshop equipment _______________________ 53...
  • Page 54 List of tools 502 71 27-02 502 71 27-02 502 51 91-01 505 69 85-70 502 71 14-01 521 54 83-01 502 71 13-01 531 00 60-76 531 03 06-23 502 51 34-02 502 50 06-01 502 50 83-01 502 71 27-02 530 03 55-60 502 51 49-01 502 71 27-02...
  • Page 55 List of tools 502 50 70-01 502 50 70-01 502 51 03-01 503 97 64-01 544 13 05-01 502 52 42-01 502 71 27-02 531 03 06-23 544 13 08-01 502 71 27-02 502 71 27-02 502 71 14-01 544 13 09-01 505 69 85-70 544 13 10-01 544 34 87-01...
  • Page 56 List of tools...
  • Page 57: Technical Data

    Technicel data Technical data Contents Engine __________________________________ 56 Ignition system ___________________________ 56 Carburettor ______________________________ 56 Clutch __________________________________ 56 Driving _________________________________ 56 Dimensions ______________________________ 56...
  • Page 58 Technicel data 122C 122LD Engine Displacement, cm 21,7 (1.32) 21,7 (1.32) Cylinder bore, mm 32,0 (1.26) 32,0 (1.26) Stroke, mm 27,0 (1.06) 27,0 (1.06) Compression ratio 8,65:1 8,65:1 Max output, kW / speed, rpm 0,6 / 6000 0,6 / 6000...
  • Page 60 115 49 33-26 2013W01...

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