STIHL Series 4140 Components BG, SH STIH)

Transcription

1 STIHL Series 440 Components BG, SH STIH)

2 Contents. Introduction. Safety Precautions 3 3. Specifications 4 3. Fuel System 4 3. Tightening Torques 5 4. Troubleshooting 7 4. Rewind Starter 7 4. Fuel System Engine 0 5. Housing 5. Handle Molding 5. Handle and Feet (BG 85, SH 85) 6. Engine 6. Removing and Installing 6. Muffler/Spark Arresting Screen Without Cat Muffler with Catalytic Converter 3 7. Rewind Starter 4 7. General 4 7. Removing and Installing Starter Cup Rope Rotor Replacing the Rewind Spring Tensioning the Rewind Spring Starter Rope Pawl 8 8. Throttle Control 8 8. Throttle Trigger 8 8. Setting Lever (BG 85, SH 85 only) Stop Switch Version up to Version from Short Circuit Wire/ Ground Wire Throttle Cable 8.6 Throttle Rod 9. Fuel System 9. Air Filter 9.. Removing and Installing 9.. Choke Shutter 9. Carburetor Leakage Test Removing and Installing Spacer Flange Servicing the Carburetor Manual Fuel Pump with Oval End Cover Manual Fuel Pump with Square End Cover Metering Diaphragm Inlet Needle Fixed Jet Pump Diaphragm and Fuel Strainer Adjusting the Carburetor Carburetor with LD Screw User Adjustment of Carburetor with H, L and LA Screws Basic Setting on Carburetor with H, L and LA Srews Tank Vent General Replacing Fuel Tank General Pickup Body Fuel Hoses Blower and Vacuum Attachment Fanwheel Protective Screen (all except BG 45) Protective Screen (BG 45 only) Blower Tube (BG only) Suction Tube (SH only) Elbow (SH only) 36. Special Servicing Tools 37. Servicing Aids 38 Series 440 Components BG, SH q ANDREAS STIHL AG & Co. KG, 05

3 . Introduction 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 440 powerhead. You will find detailed descriptions of procedures for servicing and repairing engine components in the service manual for the Series 440 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. Reference to another chapter, i.e. chapter 4. 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. Series 440 Components BG, SH

4 . Safety Precautions If the engine is started up in the course of repairs or maintenance work, observe all local and countryspecific 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. Series 440 Components BG, SH 3

5 3. Specifications 3. 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: two-stroke engine oil or brand-name two-stroke engine oil Mix ratio: 50: with STIHL 50: two-stroke engine oil Fuel mix for units with catalytic converter: Use only STIHL 50: twostroke engine oil with unleaded gasoline. 4 Series 440 Components BG, SH

6 3. 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-DG5x4 Muffler/cylinder (version with catalytic 9.0 converter) M4x7 Stub/muffler (version with spark 0.0 arresting screen in muffler) Screw IS-DG5x4 Spacer flange/cylinder 6.0 ) Collar screw P6x5/49 Collar screw/inner blower housing 4.0 ) Screw IS-DG5x4 Inner blower housing/crankcase 8.0 Screw IS-DG5x4 Inner blower housing/engine pan 8.0 Screw IS-P6x6.5 Outer/inner blower housings 5.0 Nut M8xLH-06 Fanwheel/crankshaft 7.0 (SH with shredder blade) Screw IS-P6x9 Handle/inner blower housing 5.0 3) Screw IS-P6x9 Handle molding/inner blower housing 4.0 4) Screw IS-P6x9 Fan housing/inner blower housing 6.0 Screw IS-DG5x0Z Fan housing/spiral housing 6.0 Screw IS-DG5x4 Spiral housing/crankcase 6.0 Screw IS-DG5x4 Spiral housing/engine pan 6.0 Screw IS-P6x9 Protective screen/outer blower housing 5.0 5) M4x.5 Spark plug 0.0 Remarks: ) with binding head ) SH 55, 85 only 3) BG 85, SH 85 only 4) BG 65, 85, SH 85 only 5) BG 45 only Series 440 Components BG, SH 5

7 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 DG screws max. 600 rpm max. 500 rpm Important: Do not mix up screws with and without binding head 6 Series 440 Components BG, SH

8 4. Troubleshooting 4. 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 Spring clip fatigued Fit new pawl 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 Series 440 Components BG, SH 7

9 4. 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 8 Series 440 Components BG, SH

10 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 Series 440 Components BG, SH 9

11 4.3 Engine Always check and, if necessary, repair the following parts before looking for faults on the engine: Air filter Fuel system Carburetor Ignition system ) Condition Cause Remedy Engine does not start easily, stalls at idle speed, but operates normally at full throttle Oil seals in crankcase faulty Install new oil seals ) Crankcase leaking / damaged (cracks) Muffler leaking Seal / replace the crankcase ) Seal / replace the muffler Engine does not deliver full power or runs erratically Piston rings worn or broken Install new piston rings ) Muffler / spark arresting screen carbonized Clean muffler (inlet and exhaust openings), replace spark arresting screen Air filter element dirty Fit new air filter element Fuel / impulse line kinked or cracked Fit new lines or position without kinks Engine overheating Insufficient cylinder cooling. Air inlets in fan housing blocked or cooling fins on cylinder very dirty Thoroughly clean all cooling air passages and cooling fins ) see "Series 440 Powerhead" service manual 0 Series 440 Components BG, SH

12 5. Housing 5. Handle Molding 5. Handle and Feet (BG 85, SH 85) Remove fan housing with rewind starter, b 7. Remove the spark plug. 93RA70 BG 45, 55, SH 55 only : Take out the screws () and remove the handle molding (). 93RA7 93RA7 : If necessary, replace the setting lever (), b 8. : If necessary, remove the grip molding () as follows: 93RA6 93RA6 : Take out the screws (arrows). Remove the handle. 93RA63 : Pull the grip molding () out of the guides (arrows) and lift it away. Install in the reverse sequence. : Pull the feet () upwards and out of the handle. Reassemble in the reverse sequence. BG 65, 85, SH 85 only : Take out the screws () and remove the handle molding (). Note: BG 65 has no setting lever. Series 440 Components BG, SH

13 6. Engine 6. Removing and Installing Remove fan housing with rewind starter, b 7. Remove the fanwheel, b 0. Remove the filter housing, b 9. Remove the handle molding, b 5. 93RA75 93RA76 : On machines with a throttle cable, disconnect the throttle cable () from slotted pin () on the throttle lever and push the throttle cable out of the tensioner (arrow). If necessary, remove the carburetor first. Avoid kinking the throttle cable in this process. : Remove the engine. 3 On machines with a throttle rod, remove the throttle rod, b RA73 : Disconnect the short circuit wire () and ground wire () from the ignition module. : Remove the retainers (3). 93RA74 93RA09 93RA77 Install in the reverse sequence. Observe correct tightening torques, b 3.. : When installing the engine in the inner fan housing, check that the gasket (arrow) is in front of the inner fan housing. : Pull the fuel hoses ( and ) off the elbow connectors on the carburetor. : Take engine mounting screws (arrows) out of inner fan housing. Series 440 Components BG, SH

14 6. Muffler/Spark Arresting Screen 6.. Without Cat Troubleshooting, b 4.3 Remove the fan housing with rewind starter, b 7. Install in the reverse sequence. Clean the sealing faces before installation. Install a new exhaust gasket. Apply sealant to the underside of the screw head, b. Tighten down the screws firmly, b Muffler with Catalytic Converter Troubleshooting, b 4.3 The catalytic converter integrated in the muffler is a device that helps reduce the amount of noxious emissions in the exhaust gas by initiating chemical reactions without being consumed in the process. The catalytic converter is maintenance-free. Never attempt to carry out repairs on the catalytic converter. 93RA05 93RA07 93RA08 Muffler : Take out the screws (). Spark arresting screen : On machines with a removable stub () (with and without spark arresting screen), use a 5 mm wrench to unscrew the stub. Clean the spark arresting screen or install a new stub if necessary. Clean the thread of the stub and coat it with sealant, b. Follow the sealant manufacturer s instructions. Muffler Remove the fan housing with the rewind starter, b 7. : Take the screws () out of the muffler. 93RA0 Screw home the stub and tighten it down firmly, b RA09 : Remove the muffler () and exhaust gasket (). : Remove the muffler () with exhaust gaskets () and flange (3). Series 440 Components BG, SH 3

15 7. Rewind Starter 7. General 7. Removing and Installing Install in the reverse sequence. Clean the sealing faces before installation. Install new exhaust gaskets. Spark arresting screen Remove the fan housing with rewind starter, b 7. : Take out the screw (). : Pull the spark arresting screen () out of the muffler. Clean the spark arresting screen, replace it if necessary. Install in the reverse sequence. 93RA0 Troubleshooting, b 4. If the action of the starter rope becomes very stiff and the rope rewinds very slowly or not completely, it can be assumed that the starter mechanism is in order but plugged with dirt. At very low outside temperatures the lubricating oil on the rewind spring may thicken and cause the spring windings to stick together. This has a detrimental effect on the function of the starter mechanism. In such a case it is sufficient to apply a few drops of a standard solvent-based degreasant (containing no chlorinated or halogenated hydrocarbons) to the rewind spring. Carefully pull out the starter rope several times and allow it to rewind until its normal smooth action is restored. If clogged with dirt or pitch, the entire starter mechanism, including the rewind spring, must be removed and disassembled. Take particular care when removing the spring. Clean all parts, b. Lubricate the rewind spring and starter post with STIHL special lubricant, b, before installing. : Take out the screws (+). Remove the fan housing with rewind starter. : If necessary, remove the antistatic wire (arrow). 4 Series 440 Components BG, SH

16 7.3 Starter Cup 7.4 Rope Rotor Machines with starter cup integrated in flywheel: For servicing information see the chapter on Flywheel in the Series 440 Powerhead service manual. Remove the rewind starter, b 7. Relieving tension of rewind spring 3 The rewind spring will not be under tension if the starter rope is broken. Pull out the starter rope about 0 cm and hold the rope rotor steady. While still holding the rotor steady, take three turns of the rope off the rotor. Removing The rewind spring must not be under tension. 93RA8 Pull out the starter rope a little further and then let go of the rotor. The rotor spins back so that the rewind spring is no longer under tension. : Remove the spring clip () from the starter post. : Remove the washer () and pawl (3). Carefully pull the rope rotor off the starter post. Replace the broken or worn starter rope, b 7.6 Installing Coat the bore in the rope rotor with STIHL special lubricant, b. 93RA8 : Fit the rotor on the starter post so that the driver () on the rope rotor slips behind the inner spring loop (). Series 440 Components BG, SH 5

17 7.5 Replacing the Rewind Spring Check that the spring loop has engaged by turning the rope rotor a little and letting it go. It must spring back. Coat pawl with special lubricant and install, b. Remove the rope rotor, b 7.4 Remove the pieces of broken spring from the rope rotor and starter cover. Before installing, lubricate the new spring with a few drops of STIHL special lubricant, b. : Then grip the rewind spring with pointed nose pliers about 0 mm from the end of the outer loop and place it in the starter. 93RA83 93RA84 : Fit the washer and engage the spring clip () in the groove in the starter post. : Make sure the spring clip () den engages the guide peg (arrow) on the pawl () and points clockwise. Handle the spring clip with care. The rewind starter may not function properly if the spring clip is deformed. Tension the rewind spring, b 7.5. Install the rewind starter, b 7. : Position the rewind spring in the starter and press the outer spring loop over the lug (arrow). The rewind spring may pop out and uncoil if the rope rotor is not installed very carefully. If the rewind spring has popped out, refit it as follows: Hold the spring in your hand and wind from the inside outwards and tension it to a diameter of 55 mm. : Check the distance of the inner spring loop from the hub and correct if necessary. Dimension "A" must not be more than mm. Install the rope rotor, b 7.4 Tension the rewind spring, b Series 440 Components BG, SH

18 7.5. Tensioning the Rewind Spring 7.6 Starter Rope : Make a loop in the unwound starter rope. Grip the rope close to the rotor and use it to turn the rotor six full turns clockwise. : Hold the rope rotor steady. : Pull out the rope with the starter grip and straighten it out. Hold the starter grip firmly to keep the rope tensioned. Let go of the rope rotor and slowly release the starter grip so that the rope winds itself onto the rotor. 93RA87 93RA88 The starter grip must sit firmly in the rope guide bush without drooping to one side. If this is not the case, tension the spring by one additional turn. When the starter rope is fully extended, it must still be possible to rotate the rope rotor at least another half turn before maximum spring tension is reached. If this is not the case, pull the rope out, hold the rope rotor steady and take off one turn of the rope. Do not overtension the rewind spring as this will cause it to break. Place the rewind starter in position, insert the screws and tighten them down firmly, b 3. 93RA89 Remove the rewind starter, b 7. If the starter rope is broken, remove the remaining rope from the rope rotor and starter grip. If the starter rope is worn, relieve tension of rewind spring, b 7.4. Pull the end of the rope out of the rotor and undo the knot. Then pull the worn rope out of the starter grip, housing and rotor. : Thread one end of the new rope through the rotor and housing. Tie a simple overhand knot in the end of the rope. Pull the rope back into the rotor until the knot locates in the recess. Thread the other end of the rope through the starter grip. Tie a simple overhand knot in the end of the rope. 93RA90 Series 440 Components BG, SH 7

19 7.7 Pawl 8. Throttle Control 8. Throttle Trigger 3 380RA065 93RA83 : On machines with "ElastoStart": Thread end of new starter rope through the grip () and the spring element (). Tie a simple overhand knot in the end of the rope. Pull the rope and spring element into the grip and then fit the cap (3). Tension the rewind spring, b 7.5. Install the rewind starter, b 7. Remove the rewind starter, b 7. : Ease the spring clip () off the starter post and pull the pawl () out of the rope rotor. Do not pull the rope rotor off the starter post. Coat the new pawl with special lubricant, b, and fit it in position. : Push the spring clip () into the groove in the starter post. : Make sure the spring clip () engages the guide peg (arrow) on the pawl (). The spring clip must point clockwise. Handle the spring clip with care. The rewind starter may not function properly if the spring clip is deformed. Install the rewind starter, b 7. Remove the handle molding, b 5. : On machines with a throttle cable, remove the throttle trigger () and disconnect it from the throttle cable. : On machines with a throttle rod (), remove the throttle trigger () and disconnect it from the throttle rod. Install in the reverse sequence. 93RA68 8 Series 440 Components BG, SH

20 8. Setting Lever (BG 85, SH 85 only) 8.3 Stop Switch 8.3. Version up to RA6 93RA7 93RA073 Remove the handle molding, b 5. : Ease the E-clip (8) off the setting lever s stub. : Remove the cam (7). : Pull the setting lever () with washers (, 5) and cup springs (3, 4) out of the handle molding (6). Reassemble in the reverse sequence. Slip the washers (, 5) and cup springs (3, 4) over the stub of the setting lever () and push it into the handle molding (6). Note the correct installed position of the two cup springs (3 and 4). : Fit the cam () on the setting lever s stub so that it lines up with the marking on the handle housing. : Push the E-clip () in the groove on the setting lever s stub. Assemble all other parts in the reverse sequence. : Use a flat screwdriver to ease the stop switch () out of the handle molding. : Pull the connectors () (short circuit and ground wires) off the stop switch. Install in the reverse sequence. Check correct positions of wires. Series 440 Components BG, SH 9

21 8.3. Version from Short Circuit Wire/ Ground Wire 3 93RA3 93RA0 Remove the handle molding, b 5. : Use a flat screwdriver to ease the stop switch () and protective cap () out of the handle molding. : Pull the connectors (3) (short circuit and ground wires) off the stop switch. Install in the reverse sequence. Check correct positions of wires. Remove the handle molding, b 5. Remove the stop switch, b 8.3 : Pull the connectors of the short circuit wire () and ground wire () off the ignition module. 93RA4 93RA5 BG 65, 85, SH 85 from 00 only : Remove the wire () from the housing peg. 93RA075 All BG/SH units : Pull the retainers () off the ignition lead. : Take the wires out of the guides (arrows) in the inner fan housing. Reassemble in the reverse sequence. Push home the wires so that they are properly seated in the guides in the inner fan housing. BG 45, 55, SH 55 only, from 00 Remove the throttle trigger, b 8. : Remove the wire () from the throttle trigger s pivot pin (). 0 Series 440 Components BG, SH

22 8.5 Throttle Cable 8.6 Throttle Rod 9. Fuel System 9. Air Filter Remove the handle molding, b 5. : Disconnect the throttle cable () from the throttle trigger (), b 8. : Take the throttle cable out of the guides (arrows) in the inner fan housing. Remove the carburetor, b 9.. Remove the handle molding, b 5. : Remove the throttle trigger () and disconnect the throttle rod (). : Disconnect the throttle rod () from the carburetor. Install in the reverse sequence. 93RA68 Dirty air filters reduce engine power, increase fuel consumption and make starting more difficult. If there is a noticeable loss of engine power, check to see if the air filter is plugged with dirt. Before removing the air filter, close the choke shutter and remove all loose dirt from around the filter. Wash the foam filter in a standard solvent-based degreasant containing no chlorinated or halogenated hydrocarbons and then dry. Replace if necessary. Replace the felt filter. As a temporary measure, knock the filter out on the palm of your hand or blow clear with compressed air. Do not wash. Replace multi-ply felt filter. As a temporary measure, knock the filter out on the palm of your hand or blow clear with compressed air. Do not wash If a felt filter is replaced by a multiply filter, do not re-install the foam filter. Always replace a damaged air filter immediately. : Push the throttle cable () out of the tensioner (). Remove the throttle cable. Install in the reverse sequence. Series 440 Components BG, SH

23 9.. Removing and Installing 9.. Choke Shutter Knock the filter out on the palm of your hand or blow clear with compressed air. Do not wash. Replace if heavily loaded. Always replace a damaged air filter immediately. 3 93RA : Squeeze retainers together. 93RA : Swing the filter cover () to the side and pull the lugs out of the guides (arrows). Machines with catalytic converter : Remove the gasket () and heat shield (). Use new gaskets. Install in the reverse sequence. 93RA9 Remove the air filter, b 9.. : Remove the push nut (). : Pull the choke shutter () out of the lever (3). When installing, make sure the choke shutter is properly located in the lever s guide. Use a new push nut. Install in the reverse sequence. 93RA6 93RA7 3 : Pull the filter () out of the filter housing (3). : Unscrew the nuts () and remove the filter housing. Series 440 Components BG, SH

24 9. Carburetor 9.. Leakage Test If you suspect a fault in the fuel system, see b 4.. In the case of problems with the carburetor or fuel supply system, also check or clean the tank vent, b 9.5 The carburetor can be tested for leaks with the carburetor and crankcase tester Remove the air filter, b 9.. : Push the fuel line with nipple onto the carburetor s elbow connector (arrow). 3RA08 If this pressure remains constant, the carburetor is airtight. However, if it drops, there are two possible causes:. The inlet needle is not sealing (foreign matter in valve seat or sealing cone of inlet needle is damaged or inlet control lever sticking).. Metering diaphragm is damaged. In either of these cases the carburetor has to be serviced. After completing the test, open the vent screw and pull the fuel line off the carburetor. Push the fuel hose onto the carburetor s elbow connector. Assemble all other parts in the reverse sequence. Always install a new gasket. 93RA5 3RA083 : Disconnect the fuel hose from the carburetor s elbow connector. : Connect the tester's pressure hose to the nipple. 3 43RA7 3RA084 : Push the fuel line () onto the nipple () : Close the vent screw () on the rubber bulb () and pump air into the carburetor until the pressure gauge (3) shows a reading of approx. 0.8 bar. Series 440 Components BG, SH 3

25 9.. Removing and Installing 9..3 Spacer Flange Remove the air filter, b 9.. : Remove the carburetor () and gasket (). Install in the reverse sequence. Always install the carburetor with new gaskets. 93RA33 : Disconnect the fuel hoses from from the elbow connectors on the carburetor. 93RA39 93RA34 Remove the carburetor, b 9.. : On machines with throttle cable, pull the throttle cable () out of the spacer flange (). Position the fuel hoses so that they are not kinked. Observe tightening torques, b 3. 93RA53 : On machines with throttle cable, take out the screws () and remove the spacer flange together with the hex head screws (). 93RA5 : On machines with throttle cable (), disconnect throttle cable from slotted pin () on carburetor s throttle lever. On machines with throttle rod, remove the throttle rod, b 8.6 : On machines with throttle rod, take out the screws () and remove the spacer flange together with the hex head screws (). 4 Series 440 Components BG, SH

26 9.3 Servicing the Carburetor 9.3. Manual Fuel Pump with Oval End Cover Carry out leakage test, b 9. Remove the carburetor, b RA54 : Pull the gasket () out of the guides (arrows) on the spiral housing. : Take the cap out of the end cover. Install in the reverse sequence. Always install new gaskets. Observe tightening torques, b RA3 : Take out the M3x screws (). : Remove the end cover with cap (). 936RA4 936RA05 936RA58 : Inspect the metering diaphragm and gasket and replace if necessary, b Reassemble in the reverse sequence. Additional holes in the gasket and diaphragm (if there are any) must line up with those in the carburetor and flange. : Take out the M3x8 screws (). : Remove the flange (). Series 440 Components BG, SH 5

27 9.3. Manual Fuel Pump with Square End Cover Metering Diaphragm 936RA03 : Take out the screws (). Remove the end cover with cap. : Take the cap out of the end cover. 93RA85 : Inspect the metering diaphragm and gasket and replace if necessary, b Reassemble in the reverse sequence. 936RA04 936RA05 936RA06 Remove flange from manual fuel pump with oval end cover, b 9.3. Remove flange from manual fuel pump with square end cover, b 9.3. : Remove the metering diaphragm () and gasket () from the carburetor body. If the gasket and diaphragm are stuck together, remove and separate them very carefully. : Inspect the diaphragm and gasket and replace if necessary. The diaphragm is a very delicate component. As a result of the alternating stresses the material eventually shows signs of fatigue, i.e. the diaphragm distorts and swells and has to be replaced. Reassemble in the reverse sequence. : Remove the flange. 6 Series 440 Components BG, SH

28 9.3.4 Inlet Needle Reassemble in the reverse sequence. 936RA07 936RA09 Engage clevis in annular groove on head of the inlet needle. Make sure the helical spring locates on the control lever s nipple. Check that inlet control lever moves freely. : Fit the gasket () on the carburetor body. Line up the hole in the gasket () with the compensating bore in the carburetor. Remove the metering diaphragm, b : Take out the screw (). Important: The upper edge of the inlet control lever must be flush with the top of the carburetor body. Install the metering diaphragm, b RA08 93RA60 : Place metering diaphragm () on the gasket. Line up the hole in the metering diaphragm () with the compensating bore in the carburetor and gasket. : Remove the inlet control lever (4), spindle (3), spring () and inlet needle (). Take care with the spring () because it may pop out during disassembly. Assemble all other parts, b 9.3. and RA0 : If there is an annular indentation (arrow) on the sealing cone of the inlet needle, it will be necessary to replace the inlet needle because it will no longer seal properly. Series 440 Components BG, SH 7

29 9.3.5 Fixed Jet Pump Diaphragm and Fuel Strainer Take care not to damage the fixed jet when removing. Remove the metering diaphragm, b The diaphragm is a very delicate component. As a result of the alternating stresses the material eventually shows signs of fatigue, i.e. the diaphragm distorts and swells and has to be replaced. 936RA03 Inspect the diaphragm and gasket and replace if necessary. Remove the carburetor, b 9.. : Take out the screw (). : Remove the end cover (). 936RA5 936RA RA086 CQ-S48, CQ-S50, CQ-S55 carburetors only : Unscrew the fixed jet (). : Remove the gasket (). : Examine the fuel strainer () for contamination and damage and replace if necessary RA03 936RA034 93RA59 CQ-S64, CQ-S73 carburetors only : Unscrew the fixed jet (). Reassemble in the reverse sequence. : Remove the pump diaphragm (). If the gasket and pump diaphragm are stuck together, remove and separate them very carefully. Reassemble in the reverse sequence. : The pump diaphragm () and gasket () are held in position by the pegs (arrows) on the end cover (3). 8 Series 440 Components BG, SH

30 9.4 Adjusting the Carburetor 9.4. Carburetor with LD Screw The carburetor with idle speed screw (LD) has no adjusting screws for maximum engine (H screw) or idle mixture (L screw). The carburetor is tuned so that the engine receives an optimum fuel-air mixture under all operating conditions. Standard setting LD 3RA User Adjustment of Carburetor with H, L and LA Screws H LA L 93RA303 When adjusting from scratch, first carry out the standard setting. Adjusting idle speed Carry out standard setting. Start the engine and warm it up. Standard setting The limiter cap must not be removed from the high speed screw (H) to carry out the standard setting. LD 3RA090 Engine stops while idling: : Turn the idle speed screw (LD) (arrow) slowly clockwise until the engine runs smoothly. Erratic idling behavior, poor acceleration: : Turn the idle speed screw (LD) slowly no more than half a turn counterclockwise. With this carburetor it is only possible to correct the setting of the high speed screw (H) within fine limits. Check the air filter and replace if necessary, b 9.. Check the spark arresting screen, clean or replace it if necessary, b 6. : Carefully turn the idle speed screw (LD) (arrow) counterclockwise (left-hand thread) down onto its seat. : Then turn the idle speed screw (LD) two full turns clockwise. Check the air filter and replace if necessary, b 9. Check the spark arresting screen, clean or replace as necessary, b 7. Series 440 Components BG, SH 9

31 H LA Now make the following adjustments: : Turn the high speed screw (H) counterclockwise as far as stop (no more than 3/4 turn) : Carefully turn the low speed screw (L) clockwise until it is against its seat, then open it one full turn counterclockwise. Start the engine and allow it to warm up. Fine tuning A minor correction may be necessary when operating at high altitude or at sea level. Note that even very slight corrections to the high speed screw (H) produce a noticeable change in engine running behavior. Carry out the standard setting. Start the engine and allow it to warm up. L Open the throttle wide. 93RA303 At high altitude (mountains): Turn the high speed screw (H) clockwise (leaner), but no further than stop, until there is no noticeable increase in engine speed. At sea level: Turn the high speed screw (H) counterclockwise (richer), but no further than stop, until there is no noticeable increase in engine speed. It is possible that the standard setting produces the highest engine rpm in both the above cases. Adjusting idle speed Open the low speed screw (L) one full turn. Allow the engine to warm up. Engine stops while idling Turn the idle speed screw (LA) slowly clockwise until the engine runs smoothly. Erratic idling behavior, poor acceleration Idle setting is too lean. Turn the low speed screw (L) counterclockwise (about a quarter turn) until the engine runs and accelerates smoothly. Erratic idling behavior Idle setting is too rich. Turn the low speed screw (L) clockwise (about a quarter turn) until the engine runs and accelerates smoothly. It is usually necessary to change the setting of the idle speed screw (LA) after every correction to the low speed screw (L). 30 Series 440 Components BG, SH

32 9.4.3 Basic Setting on Carburetor with H, L and LA Srews The limiter cap has to be removed from the high speed screw (H) only if it is necessary to replace the high speed screw (H), clean the carburetor or adjust it from scratch. After removing the limiter cap it is necessary to carry out the basic setting. : On carburetors with a short limiter cap (): Push the puller () , with the groove facing you, between the limiter cap () and carburetor body and pry the cap off. If the limiter cap is stuck on the screw, turn the puller over so that its groove faces the carburetor body. Pry off the limiter cap. 93RA36 : On carburetors with a long limiter cap (): Use suitable pliers to pull off the limiter cap. Screw down both adjusting screw (H and L) clockwise until they are against their seats. Now make the following adjustments: 93RA35 Adjusting idle speed Check the air filter and clean or replace as necessary. Warm up the engine. Adjust idle speed with a tachometer. Adjust specified engine speeds within a tolerance of +/- 00 rpm.. Adjust engine speed with idle speed screw (LA) to 3,300 rpm..turn low speed screw (L) clockwise or counterclockwise to obtain maximum engine speed. If this speed is higher than 3,700 rpm, abort the procedure and start again with step. 3. Use the idle speed screw (LA) to set engine speed again to 3,300 rpm 4. Set the engine speed to,800 rpm with the low speed screw (L). 5. Set maximum engine speed to 6,500 rpm with the high speed screw (H). Do not re-install used caps because they may be damaged during the removal process. Always install a new limiter cap. H L 93RA37 Open the high speed screw (H) / turns counterclockwise. Open the low speed screw (L) one full turn counterclockwise. Series 440 Components BG, SH 3

33 70 : On carburetors with a short limiter cap: Line up the new cap for the high speed screw (H) against the rich stop and press it on only as far as the second noticeable detent position. The stop limits the adjustment range of the high speed screw (H) to a 3/4 turn. Do not press the cap against the carburetor body as it will otherwise be damage. Carry out standard setting, b RA9 70 : On carburetors with a long limiter cap: Line up the new cap for the high speed screw (H) against the rich stop so that the high speed screw (H) can only be rotated a 3/4 turn clockwise. : Push on the limiter cap until it butts against the carburetor body. Carry out standard setting, b RA Tank Vent 9.5. General Correct operation of the carburetor is only possible if atmospheric pressure and internal fuel tank pressure are equal at all times. This is ensured by the tank vent. In the event of trouble with the carburetor or the fuel supply system, always check the tank vent and replace it if necessary. Testing the tank vent Open the tank cap slowly and drain the tank. Refit the tank cap, making sure it is tight. Disconnect the fuel hoses from the carburetor, b 9.. Seal one of the fuel hoses with a suitable plug. Connect vacuum pump to the other fuel hose and produce a vacuum in the fuel tank by operating the pump quickly. If the vacuum remains unchanged, install a new tank vent, b 9.5. If the vacuum slowly disappears, the tank vent is in order. 3 Series 440 Components BG, SH

34 9.5. Replacing 9.6 Fuel Tank 9.6. General If no equalization of pressures takes place, replace the tank vent. Remove the filter housing, b 9.. Note installed position of tank vent. Always use a new sealing ring. Install in the reverse sequence. Fuel tank The fuel tank is part of the inner fan housing and cannot be replaced separately. If the fuel tank is damaged, replace the complete inner fan housing. The diaphragm pump draws fuel out of the tank and into the carburetor via the fuel hose. Any impurities mixed with the fuel are retained by the pickup body (filter). The fine pores of the filter eventually become clogged with minute particles of dirt. This restricts the passage of fuel and results in fuel starvation. Always observe all safety precautions when working on the fuel system, b. In the event of trouble with the fuel supply system, always check the fuel tank and the pickup body first. Clean the fuel tank if necessary. Machines up to 00 : Pull out the tank vent (). : Pull out the grommet (). Install in the reverse sequence. 93RA096 Cleaning the fuel tank Unscrew the fuel filler cap and drain the tank. Pour a small amount of clean gasoline into the tank. Close the tank and shake the machine vigorously. Open the tank again and drain it. Dispose of fuel properly. 93RA3 Machines from 00 : Carefully pry out the tank vent () with sealing ring (). Series 440 Components BG, SH 33

35 9.6. Pickup Body Fuel Hoses Unscrew the fuel filler cap and drain the tank. Remove the fan housing with rewind starter, b 7. Remove the carburetor, b 9.. Unscrew the spark plug. Use locking strip to block the piston. Remove the blower tube and elbow, b 0.4 and b 0.6 Remove the pickup body. Unscrew the fuel filler cap and drain the tank. Pull off the tank vent, b 9.5. : Use hook () to pull the pickup body out of the fuel tank. 93RA64 : Pull the pickup body () off the fuel hose and check it for contamination, replace if necessary. Install in the reverse sequence. : Pull out the fuel hoses (arrow). Note installed position. Install in the reverse sequence. BG 55, 65, 85 only : Take out the screws and lift away the outer fan housing. 93RA6 : On BG 45, take out the screws and lift away the outer fan housing. 34 Series 440 Components BG, SH

36 0. Blower and Vacuum Attachment 0. Fanwheel 0. Protective Screen (all except BG 45) 0.3 Protective Screen (BG 45 only) 93RA63 SH 55, 85 only : Unscrew the star nut (), take out the screws and lift away the outer fan housing RA65 93RA6 93RA66 SH units only Remove suction tube, b 0.5 : Press down the retaining tab () on the protective screen and swing the screen open. : Take out the screws (). : Lift the right-hand side of the protective screen so that it comes out of the guide () 93RA67 : Unscrew the nut () clockwise (left-hand thread). : On SH 55, 85, remove the shredder blade (). : Remove the washer (3), fanwheel (4) and the washer behind it. Inspect all blades and replace fanwheel if necessary. Install in the reverse sequence. : Use a screwdriver or similar tool to press down the retaining tabs () on the outer fan housing and lift away the protective screen (). Remove the protective screen. : Before reinstalling, check the seal () for damage and make sure it is properly seated. Install in the reverse sequence. Make sure the protective screen engages in the guide. : Remove the torsion spring (arrow). Install in the reverse sequence. Series 440 Components BG, SH 35

37 0.4 Blower Tube (BG only) 0.5 Suction Tube (SH only) 0.6 Elbow (SH only) 93RA094 93RA68 : Insert a screwdriver or similar tool in the recess (arrow) on the blower stub and push the retaining tab up. At the same time, turn the blower tube counterclockwise as far as stop (/4 turn). Pull the blower tube off the stub. Fit by inserting blower tube with lug in the stub. Rotate the blower tube clockwise until the bayonet coupling engages. : Turn the suction tube counterclockwise as far as stop (/4 turn). Pull the suction tube off the stub. To fit, open the protective screen. : Loosen the star nut (). : Insert a screwdriver or similar tool in the recess (arrow) on the blower stub and push the retaining tab up. At the same time, turn the elbow counterclockwise as far as stop (/4 turn). Pull the elbow off the stub. Fit by inserting blower tube with lug in the stub. 93RA69 : Insert suction tube so that its guide slots (arrow) engage the lugs (arrow) on the stub. Rotate the suction tube clockwise until the bayonet coupling engages. : Check that rubber sealing ring (arrow) is properly seated. Rotate elbow clockwise until the bayonet coupling engages. 36 Series 440 Components BG, SH

38 . Special Servicing Tools No. Part Name Part No. Application Rem. Locking strip Blocking crankshaft Socket Installing and removing spline socket head screws with electric or pneumatic screwdrivers 3 Vacuum pump Testing crankcase and carburetor for leaks, testing tank vent 4 Carburetor and crankcase tester Testing crankcase and carburetor for leaks 5 Nipple Testing carburetor for leaks 6 Hose for leakage test Testing carburetor for leaks 7 Screwdriver Carburetor nuts Q-SW 8 x 00 8 Crimping tool Attaching connectors to electrical wires 9 Torque wrench to 8 Nm ) ) 0 Torque wrench to 80 Nm ) 3) Socket, T 7 x Installing and removing spline socket head screws with electric or pneumatic screwdrivers, tightening with torque wrench T-handle screwdriver IS screws 4) Q - T 7 x 50 3 Hook Removing pickup body Remarks: ) Always use torque wrench for tightening DG or P screws. ) Alternative: Torque wrench with optical/acoustic signal. 3) Alternative: Torque wrench with optical/acoustic signal. 4) Only use for releasing/removing DG or P screws. Series 440 Components BG, SH 37

39 . Servicing Aids No. Part Name Part No. Application Dirko gray sealant (00 g tube) Guard on muffler STIHL special lubricating oil Bearing bore in rope rotor, rewind spring 3 Standard commercial, solventbased degreasant containing no chlorinated or halogenated hydrocarbons Cleaning sealing faces 38 Series 440 Components BG, SH

40 Series 440 Components BG, SH 39

41 40 Series 440 Components BG, SH

42 englisch / English RA_95_00_0_0..J5.