STIHL BR 500 550 600 & 4140 BG SH BLOWER Workshop Manual

STIH) STIHL Series 4140 Components BG, SH 2005-01

1 Series 4140 Components BG, SH q © ANDREAS STIHL AG & Co. KG, 2005 Contents 1. Introduction 2 2. Safety Precautions 3 3. Specifications 4 3.1 Fuel System 4 3.2 Tightening Torques 5 4. Troubleshooting 7 4.1 Rewind Starter 7 4.2 Fuel System 8 4.3 Engine 10 5. Housing 11 5.1 Handle Molding 11 5.2 Handle and Feet (BG 85, SH 85) 11 6. Engine 12 6.1 Removing and Installing 12 6.2 Muffler/Spark Arresting Screen 13 6.2.1 Without Cat 13 6.2.2 Muffler with Catalytic Converter 13 7. Rewind Starter 14 7.1 General 14 7.2 Removing and Installing 14 7.3 Starter Cup 15 7.4 Rope Rotor 15 7.5 Replacing the Rewind Spring 16 7.5.1 Tensioning the Rewind Spring 17 7.6 Starter Rope 17 7.7 Pawl 18 8. Throttle Control 18 8.1 Throttle Trigger 18 8.2 Setting Lever (BG 85, SH 85 only) 19 8.3 Stop Switch 19 8.3.1 Version up to 2001 19 8.3.2 Version from 2001 20 8.4 Short Circuit Wire/ Ground Wire 20 8.5 Throttle Cable 21 8.6 Throttle Rod 21 9. Fuel System 21 9.1 Air Filter 21 9.1.1 Removing and Installing 22 9.1.2 Choke Shutter 22 9.2 Carburetor 23 9.2.1 Leakage Test 23 9.2.2 Removing and Installing 24 9.2.3 Spacer Flange 24 9.3 Servicing the Carburetor 25 9.3.1 Manual Fuel Pump with Oval End Cover 25 9.3.2 Manual Fuel Pump with Square End Cover 26 9.3.3 Metering Diaphragm 26 9.3.4 Inlet Needle 27 9.3.5 Fixed Jet 28 9.3.6 Pump Diaphragm and Fuel Strainer 28 9.4 Adjusting the Carburetor 29 9.4.1 Carburetor with LD Screw 29 9.4.2 User Adjustment of Carburetor with H, L and LA Screws 29 9.4.3 Basic Setting on Carburetor with H, L and LA Srews 31 9.5 Tank Vent 32 9.5.1 General 32 9.5.2 Replacing 33 9.6 Fuel Tank 33 9.6.1 General 33 9.6.2 Pickup Body 34 9.6.3 Fuel Hoses 34 10. Blower and Vacuum Attachment 35 10.1 Fanwheel 35 10.2 Protective Screen (all except BG 45) 35 10.3 Protective Screen (BG 45 only) 35 10.4 Blower Tube (BG only) 36 10.5 Suction Tube (SH only) 36 10.6 Elbow (SH only) 36 11. Special Servicing Tools 37 12. Servicing Aids 38

2 Series 4140 Components BG, SH This service manual contains detailed descriptions of all typical repair and servicing procedures for models BG 45, 46, 55, 65, 85, SH 55, 85, which are based on the series 4140 powerhead. You will find detailed descriptions of procedures for servicing and repairing engine components in the service manual for the “Series 4140 Powerhead“. 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" in this manual 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 a revised edition is issued. The special servicing tools mentioned in the descriptions are listed in the 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) b 4.2 Reference to another chapter, i.e. chapter 4.2 in this example. In the illustrations: A Pointer aDirection of movement 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. 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 Series 4140 Components BG, SH 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. Warning! 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

4 Series 4140 Components BG, SH 3. Specifications 3.1 Fuel System Carburetor: Diaphragm carburetor Carburetor leakage test at gauge pressure: 0.8 bar (8 kPa) Operation of tank vent at gauge pressure: 0.3 bar (3 kPa) under vacuum: 0.05 bar (0.5 kPa) Fuel: see instruction manual Octane number: min. 90 RON Fuel mixture: Regular brand-name gasoline and STIHL 50:1 two-stroke engine oil or brand-name two-stroke engine oil Mix ratio: 50:1 with STIHL 50:1 two-stroke engine oil Fuel mix for units with catalytic converter: Use only STIHL 50:1 two- stroke engine oil with unleaded gasoline.

5 Series 4140 Components BG, SH 3.2 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 Remarks Nm Screw IS-DG5x60 Muffler/cylinder 9.0 Screw IS-DG5x24 Muffler/cylinder (version with catalytic converter) 9.0 M14x7 Stub/muffler (version with spark arresting screen in muffler) 10.0 Screw IS-DG5x24 Spacer flange/cylinder 6.0 1) Collar screw P6x15/49 Collar screw/inner blower housing 4.0 2) Screw IS-DG5x24 Inner blower housing/crankcase 8.0 Screw IS-DG5x24 Inner blower housing/engine pan 8.0 Screw IS-P6x26.5 Outer/inner blower housings 5.0 Nut M8x1LH-06 Fanwheel/crankshaft (SH with shredder blade) 17.0 Screw IS-P6x19 Handle/inner blower housing 5.0 3) Screw IS-P6x19 Handle molding/inner blower housing 4.0 4) Screw IS-P6x19 Fan housing/inner blower housing 6.0 Screw IS-DG5x20Z Fan housing/spiral housing 6.0 Screw IS-DG5x24 Spiral housing/crankcase 6.0 Screw IS-DG5x24 Spiral housing/engine pan 6.0 Screw IS-P6x19 Protective screen/outer blower housing 5.0 5) M14x1.25 Spark plug 20.0 Remarks: 1) with binding head 2) SH 55, 85 only 3) BG 85, SH 85 only 4) BG 65, 85, SH 85 only 5) BG 45 only

6 Series 4140 Components BG, SH 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. Power screwdriver settings for polymer: Plastoform screws max. 600 rpm DG screws max. 500 rpm Important: Do not mix up screws with and without binding head

7 Series 4140 Components BG, SH 4. Troubleshooting 4.1 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 Spring overtensioned – no reserve when rope is fully extended Fit new rewind spring Very dirty or corroded Fit new 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 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) Coat rewind spring with a standard solvent-based degreasant (containing no chlorinated or halogenated hydrocarbons). Then pull rope carefully as often as necessary until normal action is restored

8 Series 4140 Components BG, SH 4.2 Fuel System Condition Cause Remedy Engine stalls at idle speed Idle jet bores or ports blocked Clean jet bores and ports and blow clear with compressed air Idle jet too rich or too lean Reset low speed screw (L) correctly Setting of idle speed screw (LA) incorrect – throttle shutter completely closed Reset idle speed screw (LA) correctly Engine speed drops quickly under load – low power Air filter plugged Clean the air filter or replace if necessary Tank vent faulty Fit new tank vent Leak in fuel line between tank and fuel pump Seal or renew connections and fuel line Pump diaphragm damaged or fatigued Fit new pump diaphragm Main jet bores or ports blocked Clean the bores and ports Fuel pickup body dirty Install new pickup body Setting of high speed screw (H) too rich Reset high speed screw (H) correctly Throttle shutter not opened fully Check linkage

9 Series 4140 Components BG, SH Condition Cause Remedy Poor acceleration Idle jet too lean Turn low speed screw (L) counterclockwise (richer), no further than stop Main jet too lean Turn high speed screw (H) counterclockwise (richer), no further than stop Inlet control lever too low (relative to correct installed position) Set inlet control lever flush with top of carburetor body Inlet needle sticking to valve seat Remove inlet needle, clean and refit Connecting bore to atmosphere blocked Clean the bore Diaphragm gasket leaking Fit new diaphragm gasket Metering diaphragm damaged or shrunk Fit new metering diaphragm Engine will not idle – idle speed too high Throttle shutter opened too wide by idle speed screw (LA) Reset idle speed screw (LA) correctly Carburetor floods, engine stalls Inlet needle not sealing. Foreign matter in valve seat or cone damaged Remove and clean or replace inlet needle, clean fuel tank, pickup body and fuel line if necessary Inlet control lever sticking on spindle Free off inlet control lever Helical spring not located on nipple of inlet control lever Remove inlet control lever and refit correctly Perforated disc on diaphragm is deformed and presses constantly against inlet control lever Fit new metering diaphragm Inlet control lever too low (relative to correct installed position) Fit new inlet control lever

STIHL BR 500 550 600 & 4140 BG SH BLOWER Workshop Manual

You're Reading a Preview

Recently Viewed