Stihl MS 650, MS 660 Chainsaw Service Repair Manual

STIH) STIHL MS 650, 660 2007-09

1 MS 650, MS 660 q © ANDREAS STIHL AG & Co. KG, 2007 Contents 1. Introduction 3 2. Safety Precautions 4 3. Specifications 5 3.1 Engine 5 3.2 Fuel System 5 3.3 Ignition System 5 3.4 Chain Lubrication 5 3.5 Tightening Torques 6 4. Troubleshooting Chart 8 4.1 Clutch, Chain Drive, Chain Brake, Chain Tensioner 8 4.2 Rewind Starter 10 4.3 Chain Lubrication 11 4.4 Ignition System 12 4.5 Carburetor 14 4.6 Engine 17 5. Clutch, Chain Drive, Chain Brake and Chain Tensioner 18 5.1 Clutch Drum / Chain Sprocket 18 5.2 Replacing the Chain Catcher 19 5.3 Spiked Bumper 19 5.4 Clutch 20 5.5 Chain Brake 22 5.5.1 Checking Operation 22 5.5.2 Removing 22 5.5.3 Installing 24 5.6 Chain Tensioner 27 5.7 Bar Mounting Studs 28 6. Engine 28 6.1 Muffler/Spark Arresting Screen 28 6.2 Shroud 29 6.3 Leakage Test 30 6.3.1 Preparations 30 6.3.2 Vacuum Test 31 6.3.3 Pressure Test 32 6.4 Oil Seals 32 6.5 Cylinder and Piston 34 6.5.1 Removing 34 6.5.2 Installing 36 6.6 Piston Rings 39 6.7 Crankcase/ Crankshaft 40 6.7.1 Removing the Crankshaft 40 6.7.2 Installing the Crankshaft 43 6.8 Decompression Valve 47 7. Ignition System 48 7.1 Ignition Module 48 7.2 Ignition Timing 48 7.2.1 Removing and Installing 49 7.2.2 Testing the Ignition Module 50 7.2.3 Spark Plug Boot/ Ignition Lead 51 7.3 Flywheel 52 7.3.1 Removing 52 7.3.2 Installing 53 7.4 Contact Spring 53 7.5 Testing Wiring Harness 54 7.6 Ignition System Troubleshooting 55 8. Rewind Starter 58 8.1 General 58 8.2 Removing and Installing 58 8.3 Pawls 58 8.4 Rope Rotor 59 8.5 Starter Rope / Grip 59 8.6 Tensioning the Rewind Spring 60 8.7 Segment 61 8.8 Starter Rope Guide Bushing 61 8.9 Replacing the Rewind Spring 62 9. AV System 63 9.1 Annular Buffers between Crankcase and Tank Housing 63 9.2 Annular Buffer at top of Tank Housing 64 10. Master Control / Handle System 65 10.1 Switch Shaft 65 10.2 Throttle Trigger / Interlock Lever 66 10.3 Front Handle 67 11. Chain Lubrication 68 11.1 Pickup Body / Suction Hose 68 11.2 Valve 69 11.2.1 Cleaning 69 11.2.2 Replacing 69 11.3 Oil Pump 70 11.3.1 Removing and Installing 70 11.3.2 Servicing 71 12. Fuel System 71 12.1 Air Filter 71 12.2 Carburetor 72 12.2.1 Removing and Installing 72 12.2.2 Leakage Test 74 12.3 Servicing the Carburetor 74 12.3.1 Metering Diaphragm 74 12.3.2 Inlet Needle 75 12.3.3 Fixed Jet 76 12.3.4 Pump Diaphragm 76 12.3.5 Removing and Installing the Throttle Shaft 77 12.3.6 Removing and Installing the Choke Shaft 79

2 MS 650, MS 660 Contents 12.4 User Adjustment 80 12.4.1 Carburetor without Limiter Caps 80 12.4.2 Carburetor with Limiter Caps 81 12.5 Basic Setting (Carburetor with Limiter Caps) 82 12.6 Tank Vent 84 12.7 Pickup Body 86 12.8 Fuel Hose 87 12.9 Fuel Hose in Tank 87 12.10 Separating Crankcase and Tank Housing 88 12.11 Replacing the Tank Housing 90 13. Carburetor Heating 90 13.1 Testing 91 13.2 Troubleshooting Chart 93 14. Handle Heating System 94 14.1 Troubleshooting 94 14.2 Heater Switch 95 14.3 Heating Element in Rear Handle 96 14.4 Heating Element in Front Handle 97 14.5 Generator 97 14.5.1 Troubleshooting Chart 99 14.5.2 Test Connections and Test Values 101 15. Wiring Harness 103 15.1 Standard Wiring Harness 103 15.2 Wiring Harness with Handle and Carburetor Heating 104 16. Special Servicing Tools 106 17. Servicing Aids 108

3 MS 650, MS 660 This service manual contains detailed descriptions of all the typical repair and servicing procedures for this power tool. As the design concept of models MS 650 and MS 660 is almost identical, the descriptions and servicing procedures in this manual generally apply to both models. Differences are described in detail. 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 chapter on "Troubleshooting" and the "STIHL Service Training System" for all assemblies. 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 an updated edition is issued. The special tools mentioned in the descriptions are listed in chapter "Special Servicing Tools" of this manual. Use the part numbers to identify the tools in the "STIHL Special Tools" manual which lists all the 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) +Situation applies from serial No. * Situation applies up to serial No. In the illustrations: Pointer Direction of movement b 4.2 = Reference to another chapter, i.e. chapter 4.2 in this example. Service manuals and 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 clamp (1) 5910 890 2000 is used to mount the machine on assembly stand (2) 5910 890 3100 so that one clamp screw engages the outer 10 mm hole (3) in the assembly stand. To service the underside of the machine (e.g. remove the front handle), turn it upside down and mount it so that one clamp screw engages the inner 10 mm hole in the assembly stand. Pull the hand guard back against the front handle for this purpose. Always use original STIHL replacement parts. They can be identified by the STIHL part number, the STIH) logo and the STIHL parts symbol ( This symbol may appear alone on small parts. 1. Introduction

4 MS 650, MS 660 If the engine 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. Improper handling may result in burns or other serious injuries. If parts are heated during servicing work, always wear suitable protective gloves. Do not bring any fire, flame, spark or other source of heat near the fuel. All work with fuel must be performed outdoors only. Spilled fuel must be wiped away immediately. 2. Safety Precautions

5 MS 650, MS 660 3. Specifications 3.1 Engine MS 650 MS 660 Displacement: 84.9 cm 3 91.6 cm 3 Bore: 52 mm 54 mm Stroke: 40 mm 40 mm Engine power to ISO 7293: 4.8 kW (6.5 bhp) at 9,500 rpm 5.2 kW (7.1 bhp) at 9,500 rpm Max. permissible engine speed with bar and chain: 13,500 rpm (carburetor with limiter caps) 13,000 rpm (carburetor without limiter caps) 13,500 rpm (carburetor with limiter caps) 13,000 rpm (carburetor without limiter caps) Idle speed: 2,500 rpm 2,500 rpm Clutch: Centrifugal clutch without linings Clutch engages at: 3,000 rpm 3,000 rpm Crankcase leakage test at gauge pressure: 0.5 bar 0.5 bar under vacuum: 0.5 bar 0.5 bar 3.2 Fuel System Carburetor leakage test at gauge pressure: 0.8 bar Operation of tank vent at gauge pressure: 0.3 bar Fuel: as specified in instruction manual 3.3 Ignition System Air gap between ignition module and fanwheel: 0.15 – 0.3 mm Spark plug (suppressed): Bosch WSR 6 F NGK BPMR 7 A Electrode gap: 0.5 mm 3.4 Chain Lubrication Fully automatic, speed-controlled oil pump with rotary piston Oil delivery rate: 5.5 – 15 cm 3 at 10,000 rpm

6 MS 650, MS 660 3.5 Tightening Torques DG and P screws (Plastoform) 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 Remarks Nm Screw IS-M4x8 Chain tensioner cover plate 3.0 Starter post M8 Starter post in fan housing 12.0 Screw M8x21.5 Collar screw for guide bar 23.0 1) Screw IS-M4x12 Chain brake cover 3.0 M10x 1 Decompression valve or plug 14 Screw M4x10 Spring housing/fan housing 2.5 Nut M5 Flange on filter base 2.0 Twist lock M5 Filter cover 1.0 Screw IS-M4x12 Generator (for carburetor/handle heating only) 3.5 1) Screw IS-P6x21.5 Front handle, top, with stiffener (not wrap-around handle) 7.0 Screw IS-P6x19 Front handle, top (wrap-around handle) 7.0 Screw IS-P6x19 Front handle, bottom 7.0 Screw IS-P4x19 Handle molding 1.6 Screw IS-M4x 8 Rubber buffer/crankcase 3.5 Screw IS-M5x40x25 Hand guard, left 7.0 Screw IS-M5x16 Shroud/crankcase 7.0 Screw IS-M5 Chain catcher/spiked bumper (with wrap-around handle) 6.0 Screw IS-M5x20 Chain catcher/spiked bumper/ crankcase 9.0 Screw M5x12 Spiked bumper/crankcase, top with nut 7.5 Screw IS-M5 Chain sprocket cover/spiked bumper 6.0 Screw IS-M5x20 Crankcase/oil tank housing 11.5 Remarks: 1) Loctite 243, medium strength

7 MS 650, MS 660 Fastener Thread size For component Torque Remarks Nm Screw IS-M5x20 Fan housing, magnesium 7.0 M12x1 L Clutch carrier 70.0 3) Screw IS-M4x12 Oil pump 3.0 2) Screw P6x19 Annular buffer 6.0 Screw IS-M5x16 Annular buffer/tank housing, top right 7.0 1) Screw IS-M5x12 Annular buffer plate 9.0 1) Screw IS-M5x20 Wrap-around handle with bracket 7.0 Screw M5x 6 Muffler, bottom 6.5 1) Screw IS-M6x20 Muffler, bottom/crankcase 15.0 1) Screw M5x16 Muffler/cylinder 11.5 1) Screw P4x10 Guard/tank housing 2.0 M10x1 Flywheel 45.0 4) Screw IS-M4x10 Segment/fan housing 2.5 Screw IS-M4x8 Inner side plate 3.0 Nut M5 Carburetor 3.5 M14x1.25 Spark plug 25.0 Screw M5x20 Ignition module 8.0 Screw M6x25 Cylinder/crankcase, 0.5 mm gasket 15.0 Screw M6x25 Cylinder/crankcase, 1 mm gasket 15.0 Remarks: 1) Loctite 243, medium strength 2) Install with Hylomar sealant (0783 810 1101) 3) Left-hand thread 4) Degrease crankshaft/flywheel faces and install dry 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 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. Power screwdriver setting for polymer: DG and P screws max. 500 rpm Do not use an impact screwdriver for releasing or tightening screwed assemblies. Do not mix up screws with and without binding heads.

8 MS 650, MS 660 4. Troubleshooting Chart 4.1 Clutch, Chain Drive, Chain Brake, Chain Tensioner Condition Cause Remedy Saw chain stops under load at full throttle Clutch shoes badly worn Install new clutch Clutch drum badly worn Install new clutch drum Brake band stuck Check freedom of movement and function of brake band. Saw chain rotates at idle speed Engine idle speed too high Readjust with idle speed screw (LA) (counterclockwise) Clutch springs stretched or fatigued Replace the clutch springs or install new clutch Clutch spring hooks broken Replace the clutch springs Loud noises Clutch springs stretched or fatigued Replace all clutch springs Needle cage damaged Fit new needle cage Clutch shoe retainer broken Fit new retainer Clutch shoes and carrier worn Install new clutch Chain sprocket wears rapidly Chain not properly tensioned Tension chain as specified Wrong chain pitch Fit chain of correct pitch Insufficient chain lubrication Check chain lubrication Chain sprocket worn Fit new chain sprocket

9 MS 650, MS 660 Condition Cause Remedy Saw chain does not stop immediately when brake is activated Brake spring stretched or broken Fit new brake spring Brake band stretched, worn or broken Fit new brake band Clutch drum worn Fit new clutch drum

Stihl MS 650, MS 660 Chainsaw Service Repair Manual

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