stihl hs46 and hs56 service manual

STIH) STIHL HS 46, 56 2011-03

1 HS 46, HS 46 C, HS 56 C q © ANDREAS STIHL AG & Co. KG, 2011 RA_447_00_01_01 1. Introduction and Safety Precautions 2 1.1 Introduction 2 1.2 Safety Precautions 3 2. Specifications 4 2.1 Motor 4 2.2 Fuel System 4 2.3 Ignition System 4 2.4 Gearbox Lubrication 4 2.5 Cutting Blades 4 2.6 Tightening Torques 5 3. Troubleshooting 7 3.1 Clutch 7 3.2 Cutting Attachment 8 3.3 Rewind Starter 10 3.4 Ignition System 12 3.5 Carburetor 13 3.6 Engine 16 4. Cutting Attachment with Gearbox 18 4.1 Removing and Installing 18 4.2 Cutting Blades 19 4.2.1 Sharpening the Blades 23 4.3 Spur Gear 23 4.4 Drive Pinion 24 4.5 Gearbox Housing 27 4.6 Lubricating the Gearbox 27 4.7 Clutch Drum 28 4.8 Clutch 29 5. Engine 30 5.1 Muffler 30 5.2 Leakage Test 31 5.2.1 Preparations 31 5.2.2 Vacuum Test 32 5.2.3 Pressure Test 32 5.3 Oil Seals 32 5.3.1 Ignition Side 33 5.3.2 Clutch Side 33 5.4 Housing Cover 34 5.5 Engine 34 5.6 Cylinder 37 5.7 Crankshaft 41 5.7.1 Ball Bearings 44 5.8 Piston 45 5.9 Piston Rings 47 6. Ignition System 48 6.1 Ignition Timing 48 6.2 Ignition Module 48 6.3 Testing the Ignition Module 50 6.4 Spark Plug Boot / Ignition Lead 51 6.5 Flywheel 52 6.6 Short Circuit Wire 53 6.6.1 Testing 53 6.6.2 Removing and Installing 53 6.6.3 Ground Wire 55 6.6.4 Contact Spring 56 6.7 Ignition System Troubleshooting 58 7. Rewind Starter 61 7.1 General 61 7.2 Fan housing 61 7.3 Pawl 61 7.4 Rope Rotor 62 7.4.1 Rope Rotor with ErgoStart 63 7.5 Starter Rope / Grip 64 7.6 Tensioning the Rewind Spring 65 7.7 Replacing the Rewind Spring 66 8. AV Elements 68 8.1 Annular Buffers on Cutting Attachment 68 8.2 Annular Buffers on Handle 68 8.3 Handlebar 69 9. Control Levers 70 9.1 Master Control Lever 70 9.1.1 Removing and Installing 70 9.2 Throttle Trigger / Lockout Lever 71 9.2.1 Choke Rod 73 9.2.2 Throttle Rod 74 10. Fuel System 75 10.1 Air Filter 75 10.2 Filter Housing 75 10.3 Carburetor 76 10.3.1 Leakage Test 78 10.4 Servicing the Carburetor 79 10.4.1 Metering Diaphragm 79 10.4.2 Inlet Needle 79 10.4.3 Pump Diaphragms 80 10.4.4 Lever on Throttle Shaft 81 10.4.5 Air Valve 82 10.4.6 Adjusting Screws 83 10.5 Adjusting the Carburetor 84 10.5.1 Basic Setting 84 10.5.2 Standard Setting 85 10.6 Spacer Flange 86 10.7 Tank Vent 87 10.7.1 Testing 87 10.7.2 Removing and Installing 88 10.8 Fuel Intake 88 10.8.1 Pickup Body 88 10.8.2 Fuel Suction Hose 89 10.8.3 Fuel Suction Hose in Fuel Tank 90 10.8.4 Fuel Hose – Manual Fuel Pump 91 10.8.5 Fuel Return Hose – Manual Fuel Pump 92 10.8.6 Tank Housing 93 11. Special Servicing Tools 94 12. Servicing Aids 96 Contents

2 HS 46, HS 46 C, HS 56 C 1. Introduction and Safety Precautions 1.1 Introduction This service manual contains detailed descriptions of all the repair and servicing procedures specific to this power tool. You should make use of the illustrated parts lists while carrying out repair work. They show the installed positions of the individual components and assemblies. Refer to the latest edition of the relevant parts list to check the part numbers of any replacement parts. A fault on the machine may have several causes. To help locate the fault, consult the troubleshooting charts for all assemblies and systems in this manual and the "STIHL Service Training System". Refer to the “Technical Information” bulletins for engineering changes which have been introduced since publication of this service manual. Technical information bulletins also supplement the parts list until a revised edition is issued. The special tools mentioned in the descriptions are listed in the chapter on "Special Servicing Tools" in this manual. Use the part numbers to identify the tools in the "STIHL Special Tools" manual. The manual lists all special servicing tools currently available from STIHL. Symbols are included in the text and pictures for greater clarity. The meanings are as follows: In the descriptions: : Action to be taken as shown in the illustration above the text – Action to be taken that is not shown in the illustration above the text In the illustrations: A Pointer a Direction of movement @ 4.2 Reference to another chapter, i.e. chapter 4.2 in this example Service manuals and all technical information bulletins are intended exclusively for the use of properly equipped repair shops. They must not be passed to third parties. Servicing and repairs are made considerably easier if the engine is mounted to assembly stand (3) 5910 890 3101. To do this, secure the mounting plate (2) 5910 893 9700 to the assembly stand with two screws (1) and washers. The screws must not project since they, depending on the machine, may damage housings when the machine is clamped in position. 0008RA000 TG 2 3 1 4 The third tapped hole (4) enables the plate to be mounted horizontally. The removed engine is positioned against the plate (1) 5910 893 9700 and secured with three D 5 x 24 screws (arrows) on the crankcase (2). It is also possible to mount the cutting attachment with gearbox to the plate 5910 893 9700. Place the gearbox housing against the plate so that the sleeves (arrows) engage the recess in the plate. Secure the gearbox housing to the plate (4) 5910 893 9700 with M 5 x 25 screws (1), M 5 x 65 screws (2), bushings (3) 0000 963 1008 and M 5 nuts. Alternative: Remove the gearbox cover and use M 5 x 30 screws – bushings are not necessary. 0008RA001 TG 1 2 0008RA002 TG 1 2 3 4

3 HS 46, HS 46 C, HS 56 C Preparations for servicing Fit blade scabbard before performing servicing work with the cutting attachment still mounted. Always use original STIHL replacement parts. They can be identified by the STIHL part number, the { logo and the STIHL parts symbol K. This symbol may appear alone on small parts. Storing and disposing of oils and fuels Collect fuel or lubricating oil in a clean container and dispose of it properly in accordance with local environmental regulations. 1.2 Safety Precautions If the machine is started up in the course of repairs or maintenance work, observe all local and country- specific safety regulations as well as the safety precautions and warnings in the instruction manual. Gasoline is an extremely flammable fuel and can be explosive in certain conditions. Do not smoke or bring any fire, flame or other source of heat near the fuel. All work with fuel must be performed outdoors only. Spilled fuel must be wiped away immediately. Always perform leakage test after working on the fuel system and the engine. Exercise extreme caution while carrying out maintenance and repair work on the ignition system. The high voltages which occur can cause serious or fatal accidents. Always wear suitable protective gloves for operations in which components are heated for assembly or disassembly. Improper handling may result in burns or other serious injuries. To reduce the risk of cut injuries, always wear suitable protective gloves when mounting / removing cutting blades. Always replace damaged parts. Check disassembled parts for wear or damage before re-installing – replace as necessary. Run the machine only with the housing or rewind starter mounted in position – there is otherwise a risk of injury from the flywheel and a risk of engine damage due to overheating. The chapter on tightening torques lists all machine components that have to be tightened to a specific torque or coated with threadlocking adhesive. The specifications must be maintained when tightening down screws, nuts and other fasteners in all the procedures described in this service manual. Fuel system – hose barb connectors Pull off or push on fuel hoses in line with the connector, preferably by hand, to ensure the tightness of the fuel system. Avoid damage to hose barb connectors – do not use sharp- edged pliers, screwdrivers, etc. Do not cut open fuel hoses with a knife or similar tool. Do not re-use fuel hoses after removal. Always replace with new hoses – fuel hoses may be over- stretched during removal. Install new fuel hoses either dry or with the aid of STIHL press fluid – coat ends of hoses and connectors, b 12. Other press fluids are not approved and may result in damage to the fuel hoses.

4 HS 46, HS 46 C, HS 56 C 2. Specifications 2.1 Motor HS 46, HS 46 C HS 56 Displacement: 21.4 cm 3 21.4 cm 3 Bore: 33.0 mm 33.0 mm Stroke: 25.0 mm 25.0 mm Engine power to ISO 7293: 0.65 kW at 8500 rpm 0.65 kW at 8500 rpm Cut-off speed: 9300 rpm 9300 rpm Idle speed: 2900 rpm 2900 rpm Clutch: Centrifugal clutch without linings Centrifugal clutch without linings Clutch engages at: 3500 rpm 3500 rpm Crankcase leakage test at gauge pressure: 0.5 bar under vacuum: 0.5 bar 2.2 Fuel System Carburetor leakage test at gauge pressure: 0.8 bar 0.8 bar Operation of tank vent at gauge pressure: 0.5 bar 0.5 bar Fuel: as specified in instruction manual as specified in instruction manual 2.3 Ignition System Air gap between the ignition module and flywheel: 0.25 (+ 0.15/- 0.10) mm 0.25 (+ 0.15/- 0.10) mm Spark plug (resistor type): NGK CMR 6 H BOSCH USR 4 AC NGK CMR 6 H BOSCH USR 4 AC Electrode gap: 0.5 mm 0.5 mm 2.4 Gearbox Lubrication Apply STIHL gear lubricant for hedge trimmers to open gearbox. Gear lubricant capacity: Initial capacity: 12 g Relubrication: max. 5 g Initial capacity: 12 g Relubrication: max. 5 g 2.5 Cutting Blades Bidirectional, ground on one side Bidirectional, ground on both sides Sharpening angle to horizontal: Tooth spacing: Cutting length: 35° 30 mm 450 mm, 550 mm 45° 34 mm 600 mm

5 HS 46, HS 46 C, HS 56 C 2.6 Tightening Torques DG and P (Plastoform) screws are used in polymer and light metal components. These screws form a permanent thread when they are installed for the first time. They can be removed and installed as often as necessary without impairing the strength of the screwed assembly, providing the specified tightening torque is observed. For this reason it is essential to use a torque wrench. Fastener Thread size For component Torque Nm Remarks Screw P 5x14 Filter cover/filter housing 4.0 Nut M 5 Filter housing/carburetor/spacer flange 4.0 Screw D 5x24 Guide / gearbox housing / crankcase 8.0 1) 3) Screw D 5x24 Guide / handle housing / annular buffer 6.0 1) 3) Screw P 5x18 Housing / handle housing 2.0 Screw D 5x18 Gearbox cover / gearbox housing 6.0 1) 3) Screw D 5x18 Gearbox cover / gearbox housing / guide 6.0 1) 3) Screw D 5x24 Gearbox housing / crankcase 8.0 1) 3) Screw P 6x19 Handlebar / handle housing 4.0 Screw P 4x12 Retainer / handle housing 2.0 M 8x1 L Clutch / crankshaft 17.0 Screw D 5x40 Engine pan / crankcase / cylinder, stage 1 4.0 1) 3) Screw D 5x40 Engine pan / crankcase / cylinder, stage 2 8.0 1) 3) Screw D 5x20 Fan housing / spiral housing 4.0 3) Screw M 5x25 Blade / guide / locknut 8.0 2) Screw M 5x25 Blade / thread insert (guide) 8.0 2) Screw D 5x18 Muffler / cylinder 8.0 1) 3) Nut M 8x1 Flywheel / crankshaft 25.0 4) Screw D 5x24 Spiral housing / handle housing / annular buffer 6.0 1) 3) Screw D 5x24 Spiral housing / crankcase 8.0 1) 3) M 10x1 Spark plug / cylinder 12.0 Screw D 4x18 Ignition module / cylinder 4.0 1) 3) Screw D 5x32 Spacer flange / cylinder 8.0 1) 3)

6 HS 46, HS 46 C, HS 56 C Remarks: 1) Screws with binding head 2) Micro-encapsulated screws 3) Waxed screws 4) Degrease crankshaft/flywheel and mount oil-free Use the following procedure when refitting a DG or P screw in an existing thread: Place the screw in the hole and rotate it counterclockwise until it drops down slightly. Tighten the screw clockwise to the specified torque. This procedure ensures that the screw engages properly in the existing thread and does not form a new thread and weaken the assembly. Coat micro-encapsulated screws with medium strength Loctite 242 or 243 before reinstalling. Power screwdriver setting for polymer: DG and P screws max. 500 rpm Do not use an impact wrench for releasing or tightening screws. Do not mix up screws with and without binding heads.

7 HS 46, HS 46 C, HS 56 C 3. Troubleshooting 3.1 Clutch Condition Cause Remedy Blades stop at full throttle under load Clutch shoes badly worn Install new clutch Clutch drum badly worn Install new clutch drum and check clutch, replace if necessary Blades run when engine is idling Engine idle speed too high Readjust idle speed screw LA Clutch springs stretched Install new clutch Clutch springs broken Install new clutch Loud noises Clutch springs stretched Install new clutch Clutch springs broken Install new clutch Clutch shoes and carrier worn Install new clutch Ball bearing damaged Install new ball bearing Cam plates on spur gear worn Install new spur gear Bearing shaft worn Install new gearbox housing Sleeves in blades worn Inspect blades and sleeves, replace if necessary Washers in cutting attachment worn Inspect the washers, replace if necessary

8 HS 46, HS 46 C, HS 56 C 3.2 Cutting Attachment Condition Cause Remedy Blades do not run freely or are sticking Blades are running dry Clean blade running faces and coat them with STIHL resin solvent Blades are dirty or loaded with resin Clean blade running faces and coat them with STIHL resin solvent Sleeves missing or maintaining insufficient clearance Check sleeves, install missing sleeves or replace worn sleeves Washers in guide missing or maintaining insufficient clearance between blade and guide Check washers, install missing washers or replace worn washers Guide bent Install new guide and check blades, replace bent blades Blades bent Check blades and replace if bent Retaining plate installed wrong way round Check retaining plate, replace if necessary and install properly Poor cutting performance / quality Blades are dull Sharpen the blades Clutch or clutch drum worn or damaged Inspect clutch and clutch drum, replace if necessary Blades do not run freely Clean blade running faces and coat with STIHL resin solvent, check sleeves/washers, install if missing, replace if worn, check guide and blades, replace bent parts Washers in cutting attachment worn Inspect the washers, replace if necessary Engine down on power Check carburetor and engine, replace damaged parts

9 HS 46, HS 46 C, HS 56 C Condition Cause Remedy Loud noises Drive pinion ball bearing damaged Install new ball bearing No grease in gearbox Clean and lubricate gearbox, check running faces of spur gears and blades, replace damaged parts Teeth in gearbox damaged Check the gearbox, replace damaged parts Cam plates on spur gear worn Install new spur gear Bearing shaft worn Install new gearbox housing Sleeves in blades worn Inspect blades and sleeves, replace if necessary Washers in cutting attachment worn Inspect the washers, replace if necessary Gearbox too hot No grease in gearbox Clean and lubricate gearbox, check running faces of spur gears and blades, replace damaged parts Drive pinion ball bearing damaged Install new ball bearing Blades do not run freely – too much friction in gearbox Clean blade running faces and coat with STIHL resin solvent, check sleeves/washers, install if missing, replace if worn, check guide and blades, replace bent parts Gearbox jammed Teeth in gearbox broken – fragment is jammed between gears Inspect gearbox and replace damaged parts, clean and re- lubricate gearbox

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stihl hs46 and hs56 service manual

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