Stihl MS 250 Factory Service & Work Shop Manual

STIH) STIHL MS 210, 230, 250 2003-04

1 MS 210, MS 230, MS 250 q © ANDREAS STIHL AG & Co. KG, 2007 Contents 1. Introduction 2 2. Safety Precautions 3 3. Specifications 4 3.1 Engine 4 3.1.1 Engine (USA only) 4 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 9 4.3 Chain Lubrication 10 4.4 Ignition System 11 4.5 Carburetor 12 4.6 Engine 14 5. Clutch, Chain Drive, Chain Brake and Chain Tensioner 15 5.1 Clutch Drum / Chain Sprocket 15 5.2 Chain Catcher 16 5.3 Clutch 16 5.4 Chain Brake 18 5.4.1 Checking Operation 18 5.4.2 Removing 19 5.4.3 Installing 20 5.5 Front Chain Tensioner 22 5.6 Side Chain Tensioner 22 6. Engine 23 6.1 Muffler/Spark Arresting Screen 23 6.2 Leakage Test 24 6.2.1 Preparations 24 6.2.2 Pressure Test 25 6.2.3 Vacuum Test 26 6.3 Oil Seals 26 6.4 Removing and Installing 28 6.5 Cylinder 29 6.6 Piston 31 6.7 Piston Rings 33 6.8 Crankshaft 33 6.9 Decompression Valve 34 7. Ignition System 34 7.1 Spark Plug Boot 35 7.2 Ignition Module 35 7.3 Testing the Ignition Coil 36 7.4 Checking the Wiring Harness 36 7.4.1 Ignition Timing 37 7.4.2 Removing and Installing 37 7.5 Flywheel 38 7.6 Ignition System Troubleshooting 39 8. Rewind Starter 42 8.1 General 42 8.2 Removing and Installing 42 8.3 Rope Rotor 42 8.4 Segment 44 8.5 Starter Rope 44 8.5.1 Elastostart 45 8.5.2 Tensioning 46 8.6 Rewind Spring 47 8.7 Pawl 48 9. AV Handle System/ Handle Housing 48 9.1 Annular Buffers 48 9.2 Front Handle 49 9.3 Handle Housing 50 9.4 Switch Shaft 52 9.5 Contact Spring 52 9.6 Throttle Trigger/ Interlock Lever 53 10. Chain Lubrication 54 10.1 Pickup Body 54 10.2 Connector/ Suction Hose 55 10.3 Valve 55 10.4 Worm 56 10.5 Oil Pump 57 11. Fuel System 58 11.1 Air Filter 58 11.2 Carburetor 59 11.2.1 Leakage Test 59 11.2.2 Removing and Installing 60 11.2.3 Adjusting (Carburetor without Limiter Cap) 61 11.2.4 Adjusting (Carburetor with Limiter Cap) 62 11.2.5 Standard Setting (Carburetor with Limiter Cap) 62 11.3 Tank Vent 63 11.4 Pickup Body 64 11.5 Suction Hose 64 11.6 Manual Fuel Pump 65 11.7 Hoses 65 11.8 Fuel Tank 67 12. Special Servicing Tools 69 13. Servicing Aids 71

2 MS 210, MS 230, MS 250 This service manual contains detailed descriptions of all the repair and servicing procedures specific to this power tool series. As the design concept of model MS 210, 230 and 250 chainsaws is almost identical, the descriptions and servicing procedures in thus manual generally apply to all three 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 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 chapter "Special Servicing Tools" of 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 (short) aDirection of movement (long) b 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 STIHL servicing dealers. 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 bore (3) in the assembly stand. To service the underside of the machine (e.g. remove the oil pump), turn the machine through 180 degrees and mount it so that one clamp screw engages the inner 10 mm bore (1) in the assembly stand. Note: 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

3 MS 210, MS 230, MS 250 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 owner’s manual. Gasoline is an extremely flammable fuel and can be explosive in certain conditions. Improper handling may result in burns or other serious injuries. Warning! 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. 2. Safety Precautions

4 MS 210, MS 230, MS 250 3. Specifications 3.1 Engine MS 210 MS 230 MS 250 Displacement: 35.2 cm 3 40.2 cm 3 45.4 cm 3 Bore: 40 mm 40 mm 42.5 mm Stroke: 28 mm 32 mm 32 mm Engine power to ISO 7293: 1.6 kW (2.2 HP) at 9,000 rpm 2.0 kW (2.7 HP) at 10,000 rpm 2.3 kW (3.1 HP) at 10,000 rpm Max. permissible engine speed (with bar and chain): 12,500 rpm 14,000 rpm 14,000 rpm Idle speed: 2,800 rpm Clutch: Centrifugal clutch without linings Clutch engages at: 4,100 rpm Crankcase leakage test at gauge pressure: 0.5 bar under vacuum: 0.5 bar 3.1.1 Engine (USA only) MS 210 MS 230 MS 250 Displacement: 2.15 cu. in 2.45 cu. in 2.77 cu. in Bore: 1.57 in 1.57 in 1.67 in Stroke: 1.10 in 1.26 in 1.26 in Engine power to ISO 7293: 1.5 kW (2.01 HP) 1.9 kW (2.55 HP) 2.2 kW (2.95 HP) Max. permissible engine speed (with bar and chain): 12,500 rpm 14,000 rpm 14,000 rpm Idle speed: 2,800 rpm Clutch: Centrifugal clutch without linings Clutch engages at: 4,100 rpm Crankcase leakage test at gauge pressure: 7.25 psi under vacuum: 7.25 psi

5 MS 210, MS 230, MS 250 3.2 Fuel System Carburetor leakage test at gauge pressure: 0.8 bar (11.6 psi) Function of tank vent at gauge pressure: 0.3 bar (4.35 psi) 0.05 bar (0.72 psi) Fuel: see owner’s manual 3.3 Ignition System Air gap between ignition module and fanwheel: 0.2 – 0.4 mm (0.008 – 0.015 in) Spark plug (resistor type): Bosch WSR 6F NGK BPMR 7A Electrode gap: 0.5 mm (0.02 in) 3.4 Chain Lubrication Fully automatic speed-controlled oil pump with rotary piston Oil delivery rate: approx. 7.5 cc/min (0.46 cu in/min) at 10,000 rpm

6 MS 210, MS 230, MS 250 3.5 Tightening Torques DG screws are used in the polymer and light-alloy 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 detrimentally affecting the strength of the screwed assembly, providing the specified tightening torque is observed. For this reason always use a torque wrench. Fastener Thread size For component Torque Remarks kpm Nm Spline screw IS-M4x15 Cain brake cover 0.2 2.0 Spline screw IS-D4x15 Handle molding 0.16 1.6 Spline screw IS-P5x16 Connector (engine housing/oil pump) 0.4 4.0 Spline screw IS-M4x15 Ground wire (to cylinder) 0.35 3.5 Spline screw IS-DG5x24 Handle housing/front handle 0.35 3.5 Spline screw IS-DG5x24 Hand guard 0.35 3.5 Spline screw IS-DG5x24 Fan housing 0.35 3.5 Spline screw IS-DG5x24 Buffer (to front handle) 0.35 3.5 Spline screw IS-DG5x24 Buffer (to engine housing) 0.35 3.5 Spline screw IS-DG5x24 Ignition module (to engine housing) 0.4 4 Spline screw IS-DG5x24 Cylinder (to engine housing) 0.95 9.5 Collar screw DG 8x18 Guide bar mounting 1.6 16 M12x1 Carrier (clutch) 5.0 50 M14x1.25 Spark plug 2.5 25 Collar locknut M5 Muffler 0.8 8 Collar locknut M5 Filter housing/carburetor 0.27 2.7 Collar nut M8x1 Flywheel to crankshaft 2.8 28 M12x1.5 Decompression valve 1.4 14 Spline screw IS-DG5x16 Spiked bumper 0.37 3.7

7 MS 210, MS 230, MS 250 Use the following procedure to fit a DG screw in an existing thread: – Place the DG screw in the hole and rotate it counterclockwise until 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, which would weaken the assembly. Note: Power screwdriver speed setting for polymer: – DG screws max. 500 rpm

8 MS 210, MS 230, MS 250 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 (counterclockwise) Clutch springs stretched or fatigued Replace the clutch springs 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 Saw chain does not stop immediately when brake is activated Brake spring stretched or broken Fit new brake spring Brake band stretched / worn / broken Fit new brake band

9 MS 210, MS 230, MS 250 4.2 Rewind Starter Condition Cause Remedy Starter rope broken Rope pulled out too vigorously as far as stop or over edge, i.e. not vertically Fit new starter rope Normal wear Fit new starter rope Rewind spring broken (rope does not rewind) Spring overtensioned – no reserve when rope is fully extended Fit new rewind spring Very dirty or corroded Clean or replace rewind spring Starter rope can be pulled out almost without resistance (crankshaft does not turn) Guide peg on pawl or pawl itself is worn Fit new pawl Spring clip fatigued Fit new spring clip Starter rope is difficult to pull and rewinds very slowly Starter mechanism is very dirty (dusty conditions) Thoroughly clean complete starter mechanism Lubricating oil on rewind spring becomes viscous at very low outside temperatures (spring windings stick together) Apply a few drops of kerosine (paraffin) to spring, then pull rope carefully several times until normal action is restored

Stihl MS 250 Factory Service & Work Shop Manual

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