Husqvarna 42 Workshop Manual
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Husqvarna 42 Workshop Manual

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See also: Operator's Manual
For Husqvarna Parts Call 606-678-9623 or 606-561-4983
42, 42D, 242
Workshop Manual
531 03 01-21
www.mymowerparts.com

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Summary of Contents for Husqvarna 42

  • Page 1 For Husqvarna Parts Call 606-678-9623 or 606-561-4983 42, 42D, 242 Workshop Manual 531 03 01-21 www.mymowerparts.com...

  • Page 2: Safety Statements

    The procedures included in this workshop manual are designed to provide you, the tech- nician, with the necessary information for repair and service of models 42, 42D and 242 chain saws. The information, specifications and illustrations in this publication are based on the information in effect at time of printing.
  • Page 3 For Husqvarna Parts Call 606-678-9623 or 606-561-4983 Table of Contents P a g e N o . Section © Husqvarna Forest& Garden 1995 www.mymowerparts.com...

  • Page 4: Technical Specifications

    For Husqvarna Parts Call 606-678-9623 or 606-561-4983 Technical Specifications Engine Displacement ----------------------------------------------------------- 42.0 cc (2.5 cu. in.) Bore ----------------------------------------------------------------------- 42.0 mm Stroke --------------------------------------------------------------------- 30.0 mm Maximum No Load RPM Model 242 ----------------------------------------------------------- 15500rpm Model 42(D) --------------------------------------------------------- 13000 rpm Idling Speed -------------------------------------------------------------...

  • Page 5: Service Tools

    For Husqvarna Parts Call 606-678-9623 or 606-561-4983 Service Tools pliers, spark plug 5025006-01 Assembling 5025026-01 Puller screw 5025030-07 Crankshaft installer 5025033-01 Piston stop 5025038-01 Pressure gauge 5025067-01 Wrench (11 mm) 5025070-01 Piston ring compressor 5025079-01 Seal Installer 5025082-01 Drift for fuel filter...

  • Page 6: Safety Equipment

    For Husqvarna Parts Call 606-678-9623 or 606-561-4983 Safety Equipment Chain Brake Disassembly Disengage chain brake. Remove clutch cover retaining nut and remove cover. Clean chain brake and clutch cover assembly, Remove hand guard retaining screw. Rethread screw into pivot sleeve two turns. Press on screw head to drive out inner pivot sleeve half.
  • Page 7 For Husqvarna Parts Call 606-678-9623 or 606-561-4983 Safety Equipment Remove screws (4) and cover plate. – WARNING - Wear eye protection when removing spring to prevent injury Using a screwdriver, pry out brake spring. Using a punch, drive out knee link retaining pin.
  • Page 8 For Husqvarna Parts Call 606-678-9623 or 606-561-4983 Safety Equipment Position punch in clutch cover as shown, and drive out brake band roll pin. Remove brake band and knee link assembly. Check brake band for damage or wear. The brake band thickness should not be less than 0.75 mm...
  • Page 9 For Husqvarna Parts Call 606-678-9623 or 606-561-4983 Safety Equipment Apply a thin coating of oil to brake mechanism parts. Position brake band and knee link in cover. Install knee link assembly and roll pins. Install spring on knee link mechanism.
  • Page 10 For Husqvarna Parts Call 606-678-9623 or 606-561-4983 Safety Equipment Install cover plate and secure with (4) screws. Position hand guard on clutch cover. Press pivot sleeve halves into place. Install and tighten screw. Disengage chain www.mymowerparts.com...
  • Page 11 For Husqvarna Parts Call 606-678-9623 or 606-561-4983 Safety Equipment Install bar, chain and clutch cover on saw. Test chain brake for proper operation. Inertia Chain Brake Engagement Hold the saw approximately 35 cm (14”) above a stump or other firm object. Release grip on front handle and allow front of saw to drop.

  • Page 12: Throttle Trigger Lockout

    For Husqvarna Parts Call 606-678-9623 or 606-561-4983 Safety Equipment Throttle Trigger Lockout Disassembly Press out pin and remove throttle lockout. Assembly Install throttle lockout and secure with pin. Chain Catcher Inspect chain catcher. If damage is evident, remove screw and replace chain catcher.
  • Page 13 For Husqvarna Parts Call 606-678-9623 or 606-561-4983 Starter Disassembly Remove screws (4) and starter assembly. Pull starter cord out approximately 30 cm (1 2“) and position in starter pulley recess. Carefully allow pulley to rotate counterclockwise until spring tension has been relieved.
  • Page 14 For Husqvarna Parts Call 606-678-9623 or 606-561-4983 Starter - WARNING - Wear eye protection when removing spring to prevent injury Remove center post screw and washer. Carefully withdraw starter pulley. - WARNING – Wear eye protection when removing spring to prevent injury Position starter so spring side is toward bench.
  • Page 15 For Husqvarna Parts Call 606-678-9623 or 606-561-4983 Starter Assembly - WARNING - Wear eye protection when installing spring to prevent injury Insert hook on outer end of recoil spring into starter housing as shown. Using thumbs, care- fully install new recoil spring into place.
  • Page 16 For Husqvarna Parts Call 606-678-9623 or 606-561-4983 Starter Apply a light coating of oil to starter pulley post and recoil spring. Position starter pulley on starter housing as shown. Rotate pulley to engage recoil spring in pulley. IMPORTANT: Starter pulley must be flush against recoil spring.
  • Page 17 For Husqvarna Parts Call 606-678-9623 or 606-561-4983 Starter Pull starter cord all the way out. Make sure starter pulley can be turned at least 1/2 turn, before the recoil spring fully tightens. With starter handle extended approximately 30 cm (1 2“) from housing, position starter against saw.

  • Page 18: Ignition System

    For Husqvarna Parts Call 606-678-9623 or 606-561-4983 Ignition System Description Models 42, 42D and 242 are equipped with an electronic ignition system. The spark generated by this system has a higher energy and a shorter burning time than the spark generated by a breaker point ignition.
  • Page 19 For Husqvarna Parts Call 606-678-9623 or 606-561-4983 IgnitionSvstem If no spark appears, install new spark plug or test plug P/N 50271 13-01 and pull starter handle. If no spark appears, remove ON/OFF switch lead from stop switch and pull starter handle, spark appears, stop switch is faulty and musl be replaced.
  • Page 20 For Husqvarna Parts Call 606-678-9623 or 606-561-4983 Ignition System If replacing ignition module does not restore spark, replace coil. Replacement of the Ignition Module Remove leads from ignition module. Remove screws and ignition module. Position new igni- tion module as shown and install but do not tighten screws.
  • Page 21 For Husqvarna Parts Call 606-678-9623 or 606-561-4983 Ignition System Place air gap gauge P/N 5025134-02 between ignition module and flywheel. Press ignition module against air gap gauge. Make sure flywheel magnets are in line with module and tighten ignition module screws. Remove air gap gauge.
  • Page 22 For Husqvarna Parts Call 606-678-9623 or 606-561-4983 Ignition System Using assembling pliers P/N 5025006-01, make a guide hole in high tension lead. Insert ignition lead through rubber cover and install contact spring in guide hole and secure with assembling pliers. Slide rubber cover over contact spring.
  • Page 23 For Husqvarna Parts Call 606-678-9623 or 606-561-4983 Ignition System Remove flywheel nut and washer (1). Remove starter pawls (2). Remove piston stop P/N 5025033-01. Install flywheel removal tool P/N 5025149-01 to the flywheel with the M5 screws. Ensure puller P/N 5025026-01 is centered, then tighten puller screw and lightly tap puller, and remove flywheel.

  • Page 24: Installation

    For Husqvarna Parts Call 606-678-9623 or 606-561-4983 Ignition System Remove flywheel removal tool from flywheel. Inspect starter pawls for damage or wear. Check pawl return spring tension. Replace parts as necessary. Installation Install flywheel key in crankshaft keyway and install flywheel.

  • Page 25: Heated Handles

    For Husqvarna Parts Call 606-678-9623 or 606-561-4983 Heated Handles Identification The symbol “G” means the saw is equipped with electrically heated front and rear handles. The required electric power is produced by a generator located behind the flywheel. This system requires no maintenance and is con- trolled by an ON/OFF switch on the right side of the saw.
  • Page 26 For Husqvarna Parts Call 606-678-9623 or 606-561-4983 Heated Handles Checking the Rear Handle Element With heater switch in the ‘ OFF” position, test the two heating elements in the rear handle between points 2 and 3. The meter should read 1.4 -1.8 ohms.

  • Page 27: Centrifugal Clutch

    For Husqvarna Parts Call 606-678-9623 or 606-561-4983 Centrifugal Clutch Disassembly Remove clutch cover, chain and bar. Remove cylinder cover. Remove spark plug. Thread pis- ton stop P/N 5025033-01 into spark plug hole until tight. Loosen the clutch, turn wrench in direction of arrow (clutch has left hand threads).
  • Page 28 For Husqvarna Parts Call 606-678-9623 or 606-561-4983 Centrifugal Clutch Dismantle the clutch spring. Use a pair of pliers P/N 5025049-01 and a small screwdriver. and poor function. www.mymowerparts.com...
  • Page 29 For Husqvarna Parts Call 606-678-9623 or 606-561-4983 Centrifugal Clutch Check chain sprocket and clutch drum for wear or damage. Replace as necessary. Assembly Put the spring in one of the clutch shoes so that the spring end loop lies in the middle of the shoe and mount it to the hub.
  • Page 30 For Husqvarna Parts Call 606-678-9623 or 606-561-4983 Centrifugal Clutch On 242 models, install rim sprocket on clutch drum. Install clutch drum on crankshaft. Thread clutch counterclockwise onto crankshaft. Clutch assembly must be secure on crankshaft. Apply grease to needle bearing through hole in crankshaft.

  • Page 31: Chain Lubrication System

    For Husqvarna Parts Call 606-678-9623 or 606-561-4983 Chain Lubrication System Disassembly Remove oil tank filler cap. Dispose of oil prop- erly and flush oil tank with solvent. Remove debris from tank using low pressure air. Remove clutch cover, chain, bar and clutch assembly.
  • Page 32 For Husqvarna Parts Call 606-678-9623 or 606-561-4983 Chain Lubrication System Screw oil gear puller P/N 5053818-17 com- pletely onto worm gear clockwise. Screw puller bolt into sleeve and remove worm gear from crankshaft. Tap pump housing against sturdy surface to remove sealing plug and pump piston.
  • Page 33 For Husqvarna Parts Call 606-678-9623 or 606-561-4983 Chain Lubrication System Assembly Lubricate pump parts with chain oil. Push pump piston to bottom of housing. Install and seat adjusting screw (1). Back adjustment screw out 1-1/2 turns for initial adjustment. Make sure locking tabs fit in groove of adjusting screw.
  • Page 34 For Husqvarna Parts Call 606-678-9623 or 606-561-4983 Chain Lubrication System Coat worm gear and oiler drive gear with light petroleum grease. Install oil pump and secure with screws. Install washer with labyrinth seaI against pump. Using a seal driver securely seat the washer.

  • Page 35: System Description

    For Husqvarna Parts Call 606-678-9623 or 606-561-4983 Anti-Vibration System System Description The powerhead, bar and chain are isolated from the front and rear handles by four shock mounts. These shock mounts are designed to reduce the vibration at the operator’s hands which is generated by the powerhead and the cutting equipment.

  • Page 36: Fuel System

    For Husqvarna Parts Call 606-678-9623 or 606-561-4983 Fuel System Checking the Fuel Tank Ventilation Empty fuel from tank into a suitable container. Remove cylinder cover. Remove fuel hose from carburetor. Install and tighten fuel tank cap. Connect pressure gauge P/N 5025038-01 to fuel hose.
  • Page 37 For Husqvarna Parts Call 606-678-9623 or 606-561-4983 Fuel System , . , , , _ , . # ..Carburetor WARNING - Never start chain saw without bar, chain and clutch cover installed. The clutch could come loose and cause severe injury.
  • Page 38 Using a tachometer, ensure maximum no load rpm does not exceed 14000 for 42, 42D models and 15500 for 242 models. caution: Do not adjust carburetor less than 7/8 turn open on (H) needle, this can cause an over speeding condition and possible lack of lubrication.
  • Page 39 For Husqvarna Parts Call 606-678-9623 or 606-561-4983 Fuel System Remove screw (1), washer (2), filter holder (3), gasket (4), manifold (5), gasket (6) and screw- driver guide from carburetor. Metering Side Disassembly Remove screws (1). Remove metering diaphragm cover (2) and metering diaphragm (3).
  • Page 40 For Husqvarna Parts Call 606-678-9623 or 606-561-4983 Fuel System If leakage occurs, loosen screw and remove needle valve. Inspect needle valve (1) and lever (2) for wear or damage. Replace if necessary. Check shafts (1), choke and throttle plates (2), springs (3) and fast idle levers (4) for wear or damage.

  • Page 41: Fuel Pump

    For Husqvarna Parts Call 606-678-9623 or 606-561-4983 Fuel System Fuel Pump Disassembly Remove screw (l). Remove fuel pump cover (2), gasket (3) and diaphragm (4). NOTE: The internal passages of the carbure- tor body are delicate and are easily damaged if proper service procedures are not used.
  • Page 42 For Husqvarna Parts Call 606-678-9623 or 606-561-4983 Fuel System Install choke (1) and throttle assemblies. Install needle valve (3), spring (4), lever (5) and pin (6). Secure with screw (7). Metering lever must be level with metering diaphragm mounting area of carburetor. Adjust if necessary.
  • Page 43 For Husqvarna Parts Call 606-678-9623 or 606-561-4983 Fuel System Replace fuel inlet screen (1). Assemble fuel pump diaphragm, gasket and cover as shown and secure with screw (2). Be sure fuel inlet fitting is angled correctly. Pressure test carburetor as outlined earlier in this section.
  • Page 44 For Husqvarna Parts Call 606-678-9623 or 606-561-4983 Fuel System Assemble screws and washers (1), filter holder (2), carburetor (3), gasket (4), manifold (5), gasket (6) and screwdriver guide (7). Installation of Carburetor Connect throttle linkage to carburetor. Position carburetor as shown and tighten screws (1). Be sure fuel hose (2) is at least 95 mm (3-3/4 in.)
  • Page 45 For Husqvarna Parts Call 606-678-9623 or 606-561-4983 Fuel System Disassembly Remove cylinder cover and air filter. On Model 42D the compression release valve located on the clutch (right) side of the cylinder can be removed for inspection or replaced if necessary by using a 13 mm socket.

  • Page 46: Cylinder And Piston

    For Husqvarna Parts Call 606-678-9623 or 606-561-4983 Cylinder and Piston Remove carburetor and muffler. Clean exhaust port. Check spark screen, clean or replace. Place piston ring in cylinder approximately 1/2 way down and check ring gap. NOTE: Proper ring gap is 0.25-0.30 mm (0.010”...
  • Page 47 For Husqvarna Parts Call 606-678-9623 or 606-561-4983 Cvlinder and Piston Assembly NOTE: Replace all gaskets when reassem- bling piston/cylinder. Position piston on connecting rod with arrow on piston top facing the exhaust side as shown. Apply a few drops of oil to wrist pin, Push wrist pin into place.
  • Page 48 For Husqvarna Parts Call 606-678-9623 or 606-561-4983 Lower cylinder down onto piston. Gently push cylinder down until ring has entered the cylin- der. Remove piston ring compressor. Secure cylinder with screws. (Be sure cylinder gasket is aligned properly before installing cylinder.) Secure muffler support to crankcase...
  • Page 49 For Husqvarna Parts Call 606-678-9623 or 606-561-4983 Cylinder and Piston Changing a Bar Stud Empty and rinse out the oil tank. Using a drift punch, tap the bar stud into the oil tank. Extract the stud through the oil filler opening. Insert a smaller diameter wire through the bar stud hole in the crankcase and out the oil filler opening.

  • Page 50: Crankcase And Crankshaft

    For Husqvarna Parts Call 606-678-9623 or 606-561-4983 Crankcase and Crankshaft Crankcase Disassembly Remove the oil pump (see Section 8), flywheel (see Section 5), piston and cylinder (see Section 11). Remove the four rubber elements and separate the crankcase from the tank.

  • Page 51: Checking The Crankshaft

    For Husqvarna Parts Call 606-678-9623 or 606-561-4983 Crankcase and Crankshaft Mount the tool on the left crankcase half and press out the crankshaft. Remove the crankshaft bearings from the crankcase halves by heating up the crankcase around the crankshaft bearing then pressing the bearing out of the case.
  • Page 52 For Husqvarna Parts Call 606-678-9623 or 606-561-4983 Crankcase and Crankshaft Very carefully inspect the connecting rod big- end (crank pin) bearing. Hold the connecting rod flush against one crank half and then the other while rotating the rod around the pin.
  • Page 53 For Husqvarna Parts Call 606-678-9623 or 606-561-4983 Crankcase and Crankshaft Assembly Thoroughly clean all parts before assembly. Make sure the crankcase half mating surfaces are clean and free of all gasket material. Heat the bearing seat area of the ignition (left) side crankcase half and install the crankshaft bear- ing.
  • Page 54 For Husqvarna Parts Call 606-678-9623 or 606-561-4983 Crankcase and Crankshaft Position the crankcase gasket onto the ignition side crankcase half using a light coating of grease to hold it in place. NOTE: The crankcase alignment pins should be located in the ignition side crankcase half.
  • Page 55 For Husqvarna Parts Call 606-678-9623 or 606-561-4983 Crankcase and Crankshaft Always use new crankshaft seals. Begin with the ignition side. Apply grease to the crankshaft seal lip and carefully slide the seal over the end of the crankshaft. The open side of the seal must face inward.
  • Page 56 For Husqvarna Parts Call 606-678-9623 or 606-561-4983 www.mymowerparts.com...
  • Page 57 For Husqvarna Parts Call 606-678-9623 or 606-561-4983 www.mymowerparts.com...
  • Page 58 For Husqvarna Parts Call 606-678-9623 or 606-561-4983 NOTES www.mymowerparts.com...

This manual is also suitable for:

42d242

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