Stihl 088 Workshop Manual
Contents
1. e Use the clamping strap 1 Remove the clamping strap and 0000 893 2600 to compress the wooden assembly block piston rings around the piston e To fit the manifold in the tank Check that the piston rings are housing intake opening wind a correctly positioned piece of string 1 about 15 cm 6 long around the back of the Lubricate the inside of the cylinder manifold flange and pass the with oil and line it up so that it is ends of the string through the positioned as it will be in the intake opening installed condition It is important to observe this point as the piston e Push the manifold down rings might otherwise break Carefully line up the cylinder and gasket e Fit cylinder base screws and torque down to 15 0 Nm 11 0 Ibf ft in diagonal pattern Assembly is now a reversal of the disassembly sequence e Slide the cylinder over the piston e Pull the ends of the string the clamping strap is pushed outward downward as the piston rings slip into the cylinder STIHL 088 23 4 6 Piston Rings 4 7 Crankcase 4 7 1 Removing the Crankshaft Remove the piston see 4 5 1 Remove the clutch see 3 2 Remove rings from piston Remove the chain brake see 3 3 1 Remove the cylinder see 4 5 1 Remove the flywheel see 5 3 Drain the oil tank Drain the fuel tank Note Dispose of fuel at approved disposal site Important Heat the screws Take care not to overheat2. Reassemble in the reverse sequence Check that upper and lower grommets are properly seated Distance a between terminal and insulating tube should be 15 mm 0 6 in 37 6 REWIND STARTER 6 1 General 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 paraffin kerosine to the rewind spring Then 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 special care when removing the spring Wash all parts in paraffin or white spirit Lubricate the rewind spring and starter post with STIHL special lubricant see 11 2 before installing STIHL 088 6 2 Rewind Spring 6 2 1 Replacing Caution The rewind spring may pop out and uncoil during installation Troubleshooting chart see Standard Repairs Troubleshooting handbook If the rewind spring has popped out refit it as follows Remove the fan housing see 5 1
3. The thumb operated Master Control e Take out the screw 1 Reassemble in the reverse lever moves the switch shaft to select sequence the required function e Remove the right hand pivot mount 2 Hold the contact spring up while The following positions can be installing the switch shaft selected with the Master Control e Disconnect the throttle rod 3 lever STOP 1 closes short circuit contact and interrupts ignition RUN 2 normal operating position START 3 warm start starting throttle choke shutter open CHOKE 4 cold start starting throttle choke shutter closed Remove throttle rod from e Ease the switch shaft out of its carburetor see 10 2 1 left hand pivot mount Remove the switch shaft e Pull short circuit wire out of the e Remove the choke lever 1 and switch shaft double lever 2 STIHL 088 41 8 2 Throttle Trigger Interlock Lever Remove the filter base see 10 1 e Use a5 mm 3 16 drift to drive e Fit the handle molding and make out the dowel pin 1 sure it engages properly e Take out the screw e Take out the throttle trigger 2 Fit the filter base see 10 1 Remove the handle molding with torsion spring 3 Move Master Control lever to e Remove the torsion spring from Run position the throttle trigger e Take out the interlock lever The torsion spring must be fitted under the interlock lever and locate in the notch e Pull the
4. replaced After finishing the test open the vent screw and disconnect the hose Remove the test flange Install the carburetor see 10 2 1 Remove the test flange with clamp Install the muffler see 4 1 Unscrew the plug from the cylinder Install decompression valve see 4 8 18 4 3 Oil Seals It is not necessary to disassemble Clamp the arms Wait about one minute then turn the the complete crankcase if only the crankshaft several times oil seals have to be replaced Pull out the oil seal Install the flywheel see 5 3 Starter side Important Take special care not to damage crankshaft stub Remove the flywheel see 5 3 Clutch side Clean sealing face on crankshaft stub with standard commercial Remove the spur gear see 9 3 solvent based degreasant containing no chlorinated or Fit No 3 1 jaws 0000 893 3706 to halogenated hydrocarbons the puller see 11 2 Lubricate sealing lips of oil seal with grease see 11 2 Thinly coat the outside diameter of the oil seal with sealant see 11 2 Push the oil seal over the crankshaft stub the open side must face the crankcase e Remove key from crankshaft e Apply puller 1 5910 890 4400 Use a suitable pipe or punch to Clamp the arms carefully tap the oil seal and free it off Pull out the oil seal Important Take special care not to damage crankshaft stub Clean sealing face on crankshaft s
5. 5 8 psi If this pressure remains constant the carburetor is airtight However if it drops there are two possible causes 1 The inlet needle is not sealing foreign matter in valve seat or sealing cone of inlet needle is damaged or inlet control lever sticking The metering diaphragm is damaged In either of these cases the carburetor must be removed and serviced 49 10 2 3 Adjustment Standard setting If the carburetor has to be adjusted from scratch first carry out the standard setting Carefully screw down both adjusting screws until they are hard against their seats Then make the following adjustments H Open high speed screw 1 1 full turn L Open low speed screw 2 1 full turn A slight correction may be necessary if the saw is used at high altitudes mountains or at sea level For corrections to high speed screw H Use a tachometer do not exceed max permissible engine speed Engine can be damaged by lack of lubricant and overheating Maximum engine speed with bar and properly tensioned chain 12 000 rpm Note If no tachometer is available do not turn the high speed or low speed screws beyond the standard setting to make the mixture leaner STIHL 088 e Check chain tension e Check air filter and clean if necessary e Adjust idle speed correctly chain must not rotate e Start the saw warm up the engine Turn high speed screw H and
6. Oil Pump 9 4 1 Removing and Installing 9 4 2 Servicing Always check the suction hose and pickup body before disassembling the oil pump Remove the oil pump see 9 4 1 Remove the spur gear see 9 3 e Take the sealing ring out of the crankcase bore e Take out the screws 1 Reassemble in the reverse e Remove the cover 2 sequence e Take out the screws 1 e Ease the spur gear off the pump e Remove the cover 2 e Take out the screws e Pry away the oil pump Pull out the oil pump STIHL 088 45 lt gt lt e Use a2 mm 5 64 drift to drive out the spring pin 1 e Pull out the control bolt 2 e Remove the 0 rings 3 e Pry the plug 4 out of the housing e Take out the pump piston 5 with spring 6 and washer 7 e Remove the shaft seal 8 e Pull out the worm 9 Wash all parts in white spirit Inspect the parts for damage and replace as necessary Reassemble in the reverse sequence Always install new O rings Coat pump piston and worm with grease see 11 2 before installing STIHL 088 Place punp housing 1 on base 2 1124 893 5200 e Use press plate 1 1124 893 5100 to install spur gear Clean sealing face with a standard commercial solvent based degreasant containing no chlorinated or halogenated hydrocarbons see 11 2 Lubricate lips of shaft seal with grease see 11 2 Apply thin coating of sealant see 11 2 to circu
7. Use press arbor 1 1124 893 7200 to press the ball bearing out of its seat If necessary remove snap ring from bearing seat e Carefully knock the oil seal out of the starter side of the crankcase e Use press arbor 1 1119 893 2401 to remove the ball bearing Push the annular buffer 1 out of the starter side of the crankcase e Unscrew the oil tank filler cap 2 e Remove cord 3 from the groove STIHL 088 ite e Pull out the oil suction hose with pickup body Push the annular buffer out of the clutch side of the crankcase e Push the stop buffer out of its seat Note To replace the crankcase carry out the following operations 27 4 7 2 Installing the Crankshaft New crankcases come with preassembled ball bearings Stamp the machine number on the crankcase with 2 5 mm 0 1 figure stamps If the original crankcase is used again remove the gasket residue and clean the mating surfaces they must be cleaned very thoroughly to ensure a perfect joint e Remove the complete chain tensioner see 3 4 Heat area of bearing seat on clutch side of crankcase to approx 150 C 300 F Place ball bearing in position with stepped edge 1 down and push it home by hand as far as stop Note This operation must be e Check that snap ring is fitted in the clutch side of the crankcase e f necessary use stud puller 1 5910 893 0506 to unscrew the collar
8. located in their retainers Coat threads of front handle mounting screws with Loctite see 11 2 and torque down to 8 0 Nm 5 9 Ibf ft STIHL 088 55 11 11 1 No 17 19 20 21 22 23 24 26 27 29 30 31 32 33 Special Servicing Tools and Aids Special Servicing Tools Part Name Locking strip for piston Flange Clamp Wooden assembly block Clamping strap Test flange Sleeves Carburetor and crankcase tester Vacuum pump Nipple Fuel line Plug Puller Jaws No 3 1 Press sleeve Assembly sleeve Assembly drift Installing tool 12 Stud puller M8 Setting gauge Assembly hook Assembly stand Clamping bar Assembly tube Service tool AS Screw sleeve Service tool ZS Screws Screw sleeve Torque wrench Torque wrench Base Press plate STIHL 088 Part No 0000 893 5903 1124 850 4205 0000 890 4400 1108 893 4800 0000 893 2600 1106 850 4201 1127 851 8300 1106 850 2905 0000 850 3501 0000 855 9200 1110 141 8600 1122 025 2200 5910 890 4400 0000 893 3706 1127 893 2400 1124 893 4600 1111 893 4700 5910 890 2212 5910 893 0506 1111 890 6400 5910 893 8800 5910 890 3100 1117 890 0900 5910 007 2205 5910 893 2421 5910 007 2220 9022 341 1190 5910 893 2408 5910 890 0301 5910 890 0302 5910 890 0311 5910 890 0312 1124 893 5200 1124 893 5100 Application Rem Blocking crankshaft Sealing exhaust port for leakage test Securing flange f
9. low speed screw L clockwise for leaner mixture at high altitudes or counterclockwise for richer mixture at sea level Turn screws very slowly and carefully even slight adjustments produce a noticeable change in engine running behavior Note the following when making corrections to high speed screw The setting of the high speed screw H affects the maximum off load engine speed If the setting is too lean the maximum permissible engine speed will be exceeded and increase the risk of engine damage Adjusting idle speed A correction at the low speed screw L usually necessitates a change in the setting of the idle speed screw LA Engine stops while idling Check standard setting Turn idle speed stop screw LA clockwise until the chain begins to run then turn it back one quarter turn Chain runs while engine is idling Check standard setting Turn the idle speed stop screw LA counterclockwise until the chain stops running and then turn it about another quarter turn in the same direction Erratic idling behavior poor acceleration Idle setting too lean Turn the low speed screw L counterclockwise until the engine runs and accelerates smoothly 50 10 3 Tank Vent 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 Important In the event of trouble with the carbu
10. not use pointed or sharp edged tools e Carefully separate the cylinder gasket from the cylinder base e Unscrew the spark plug Reassemble in the reverse sequence Pull the cylinder off the piston 20 4 5 2 Installation e Release the hose clamp 1 e Pull the manifold 2 off the intake port Inspect the cylinder and replace it if necessary If a new cylinder has to be installed always fit the matching piston New cylinders are only supplied complete with piston for this reason Before removing the piston decide whether or not the crank shaft has to be removed as well To remove the flywheel block the crankshaft by sliding the wooden assembly block between the piston and crankcase Remove the cylinder gasket e Use the assembly drift 2 1111 893 4700 to push the piston pin 1 out of the piston Note If the piston pin is stuck tap the end of the drift lightly with a hammer if necessary Important Hold the piston steady during this process to ensure that no jolts are transmitted to the connecting rod Remove piston and take the needle cage out of the connecting rod Thoroughly clean the gasket seating surface 1 Lubricate the needle cage 2 with oil and fit it in the small end To ease assembly heat the piston slightly and slip it over the connecting rod Check installed position of piston 1 Mark 2 Flywheel e Ease the hookless snap rings out
11. plastics Remove the oil pump see 9 4 1 e Remove front handle mounting screws from side of machine e Use a piece of old piston to e Hold the self locking nut steady e Remove front handle mounting scrape the grooves clean and take out the screws screws from underside of machine Lift away the front handle e Install the new piston rings in the e Take out the screw 1 e Take out the screws grooves so that the radii face upward e Remove the spiked bumper 2 Remove the ignition module with deflector 3 Install the piston see 4 5 2 STIHL 088 24 171RA084VA gt e Remove the piston see 4 5 1 e Pry the plug out of the annular e Take the screws out of the annular buffer at the starter side buffers Lift the crankcase away from the tank housing 171A 171RA085 VA e Pull impulse hose off the nipple e Take the screw out of the e Unscrew the mounting screws annular buffer which join the two halves of the crankcase e Take out the screws e Pry the plugs out of the annular e Atchain tensioner side of crank buffers at the clutch side case use a 5 mm 3 16 drift 2 to drive the dowel pin 1 out of the two halves of the crankcase STIHL 088 25 Back off spindle 1 of service tool AS 5910 007 2205 all the way Slip service tool AS 2 over the collar studs fit the hexagon nuts 3 for sprocket cover and tighten them down by hand Turn the spi
12. 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 it might break Refit the fan housing see 5 1 2 e Hold the rope rotor steady e Pull out the rope with the starter grip and straighten it out 39 7 AV HANDLE SYSTEM Rubber anti vibration buffers are installed between the engine housing and handle frame Damaged rubber buffers annular buffers must always be replaced Remove the shroud see 4 8 e Take out the center screw 1 e Remove the support 2 e Take out the screws 3 e Remove the annular buffer 4 Note Remove the tank housing see 10 6 for access to the other annular buffers STIHL 088 e Pry the annular buffers out of the e Atclutch side push annular buffer crankcase home from outside until its groove 1 engages the housing rib 2 N e Push the stop buffer out of its e At the starter side push annular seat and take it away buffer home from outside until its groove 1 engages the housing rib 2 Assembly is now a reversal of the disassembly sequence W e Push the stop buffer into the guide until the groove 1 engages the housing rib 2 40 8 MASTER CONTROL HANDLE SYSTEM 8 1 Switch Shaft
13. tag 3 for the short circuit wire Accurate testing of the ignition module is only possible with sophisticated test equipment For this reason itis only necessary to carry out a spark test in the workshop A new ignition module must be installed if no ignition spark is obtained after checking that wiring and stop switch are in good condition 33 5 1 1 Ignition Timing Ignition timing is fixed and is not adjustable Since there is no mechanical wear in these systems ignition timing cannot get out of adjustment However an internal fault in the circuit can alter the switching point in such a way that a spark test will still show the system to be in order although timing is outside the permissible tolerance This will impair engine starting and running behavior STIHL 088 5 1 2 Removing and Installing 171RA139 VA Remove carburetor box cover see 10 1 Remove the shroud see 4 8 e Take out the screws Remove the fan housing 171RA140 VA e Pull the short circuit wire 1 off the connector tag on the ignition module and out of the retainer 2 lt lt c a 171RA142 VA If necessary pry the pin of the wire retainer out of the ignition module e Remove wire retainer Refit retainer before installing the ignition lead see 5 2 Coat threads of screws with Loctite 242 see 11 2 Place the module in position insert the screws with washers but do not tigh
14. the clutch side e Take out the annular buffer mounting screws 171RA219 VA lt gt o amp y lt T E 53 To replace the impulse hose An M6x18 pan head screw must remove the fuel hose switch shaft then be used in place of the original throttle lever and tank vent special self threading screw Reassemble in the reverse sequence e Pull the tank housing forward and Note If a screw thread is stripped in push the manifold flange out of the one of the mounting holes for special tank housing at the same time self threading screws the tank housing can be repaired by installing a thread insert e Pull the impulse hose off the e The stripped thread must be e Fit the manifold in the tank housing nipple drilled out to a diameter of intake opening as follows Wind a a 8 5 mm and a depth of piece of string 1 b 15 mm approx 9 16 approx 15 cm 6 long around the back of the manifold flange Caution Do not exceed the Pass the ends of the string through specified hole depth of 15 mm the intake opening e Push the manifold down e Remove the rings from the tank e Fit an M6x10 screw with washer in housing the thread insert Screw the thread insert into the tank housing STIHL 088 54 e Pull the ends of the string outward Note The manifold flange is thus pulled through the tank housing intake opening without damaging the manifold e All wires must be properly
15. 2 Remove the rope rotor see Standard Repairs Troubleshooting handbook remove any remaining pieces of spring from the fan housing Note The replacement spring comes ready for installation and is held by a wire retainer It should be lubricated with a few drops of STIHL special lubricant before installation see 11 2 Engage the outer anchor loop in the recess and then fit the spring in the clockwise direction in the fan housing starting outside and working inwards Check position of inner spring loop relative to bore i e a 2 mm 0 08 in and correct if necessary e Fit the rewind spring so that its outer anchor loop engages the recess in the fan housing The wire retainer slips off as the spring is pressed into place 38 Install the rope rotor see Standard Repairs Troubleshooting handbook Tension the rewind spring see 6 2 2 STIHL 088 6 2 2 Tensioning 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 onto the rotor e Make a loop in the starter rope e Grip the rope close to the rotor Note The rewind spring is correctly and use it to turn the rope rotor tensioned when the starter grip sits six full turns clockwise 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
16. 500 rpm with 7 tooth 0 404 sprocket Fully automatic speed controlled reciprocating oil pump no oil feed at idle speed Additional manual oil flow control with E matic mark Adjustable 17 38 cm min 0 6 1 3 fl oz min at 10 000 rpm 0 70 1 1 48 US pt 2 5 Special Accessories 1124 900 5001 0000 120 1650 1124 007 1005 2 5 1 For User STIHL repair kit 084 088 HD air filter kit Intake air preheating kit 1124 007 1061 1124 007 1051 2 5 2 For Service Carburetor parts kit Gasket kit 088 2 6 Tightening Torques Plastoform screws are used for polymer 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 it is essential to use a torque wrench Fastener Thread size For component Torque Remarks Nm Ibf ft Spline screw IS B3 9x13 Cover plate sprocket cover 1 5 1 1 Spline screw IS B3 9x19 Tank housing handle molding 1 0 0 75 Spline screw IS B3 9x19 Switch shaft pivot tank housing 1 0 0 75 Spline screw IS M4x8 Cover plate chain tensioner 3 0 2 2 Spline screw IS M4x8 Inner side plate crankcase 3 0 2 2 Spline screw IS M4x12 Segment fan housing 2 5 1 8 Spline screw IS M4x12 Oil pump crankcase front bottom rear 3 5 2 6 Spline screw IS M4x12 Chain brake cover crankcase 3 0 2 2 Spline screw IS M4
17. CONTENTS 1 Introduction 2 Specifications 2 1 Engine 2 2 Fuel System 2 3 Ignition System 2 4 Cutting Attachment 2 5 Special Accessories 2 5 1 For User 2 5 2 For Service 2 6 Tightening Torques 3 Clutch Chain Drive Chain Brake and Chain Tensioner 3 1 Clutch Drum Chain Sprocket 3 2 Clutch 3 3 Chain Brake 3 3 1 Disassembly 3 3 2 Assembly 3 3 3 Checking Function 3 3 4 Brake Spring Anchor Pin 3 3 5 Hand Guard Pivot Pin 3 4 Chain Tensioner 4 Engine 4 1 Exhaust Muffler Spark Arresting Screen 4 2 Leakage Test 4 2 1 Preparations 4 2 2 Pressure Test 4 2 3 Vacuum Test 4 3 Oil Seals 44 Exposing the Cylinder 4 5 Cylinder and Piston 4 5 1 Removal 4 5 2 Installation 46 Piston Rings 47 Crankcase 4 7 1 Removing the Crankshaft 4 7 2 Installing the Crankshaft 48 Decompression Valve STIHL 088 ann nak BW Ww E NOOOON 13 14 15 15 16 17 18 20 20 20 21 24 24 28 32 _ d No 5 3 5 4 5 5 6 1 6 2 6 2 1 6 2 2 9 1 9 2 9 4 9 4 1 9 4 2 Ignition System Ignition Module Ignition Timing Removing and Installing Spark Plug Boot Ignition Lead Flywheel Ground Wire Short Circuit Wire Contact Spring Rewind Starter General Rewind Spring Replacing Tensioning AV Handle System Master Control Handle System Switch Shaft Throttle Trigger Interlock Lever Chain Lubrication Pickup Body Suction Hose Valve Spur Gea
18. Pull off the clutch drum chain Note If the clutch drum has to be pulling the hand guard toward sprocket replaced also check the brake the front handle band see 3 3 e If the clutch drum is still serviceable use No 120 emery paper or emery cloth grain size approx 120um to clean and roughen its friction surface Reassemble in the reverse sequence Clean stub of crankshaft Wash needle cage in clean white spirit and lubricate with grease see 11 2 Replace damaged needle cage Rotate clutch drum chain sprocket and apply slight pressure at the same same until oil pump drive spring engages properly a gt z wu lt a 5 lt e Remove the E clip 1 e Take the needle cage out of the sprocket e Remove the washer 2 Clean and inspect the clutch drum chain sprocket STIHL 088 7 3 2 Clutch Troubleshooting chart see Standard Repairs Trouble shooting handbook Remove clutch drum chain sprocket see 3 1 Remove decompression valve see 4 8 e Unscrew the clutch from the e Screw clutch onto crankshaft and crankshaft in the direction of the torque down to 80 Nm arrow left hand thread 59 Ibf ft Disassemble and reassemble the Remove locking strip from clutch see Standard cylinder Repairs Troubleshooting handbook Install spark plug and torque down to 25 Nm 18 5 Ibf ft Remove the cover washer Important If spark plug has a separate ter
19. Remove carburetor see 10 2 1 Disconnect the pickup body see 10 4 Pull off the outer fuel hose Pickup body e Use the assembly hook 1 5910 893 8800 to pull the pickup body out of the fuel tank Note Do not stretch the fuel hose while removing it e Pull the pickup body off the fuel e Pull out the fuel hose e Pry the flange of the fuel hose hose out of the fuel tank Fit anew pickup body Pull out the fuel hose Reassemble in the reverse Reassemble in the reverse sequence sequence e Pull fuel hose 1 off the Coat the flange of the fuel hose connector 2 with a little oil e Straight side 1 of flange must locate against tank housing STIHL 088 52 10 6 Tank Housing Drain the tank housing Note Collect fuel in a clean container or dispose of it at an approved disposal site Remove carburetor see 10 2 1 e Take the sleeve out of the manifold Important Heat the screwed joints Do not overheat polymer e Remove the mounting screws from the side of the front handle STIHL 088 e Take out the front handle mounting screws on the under side of the machine Remove the front handle Remove the short circuit and ground wires see 5 4 e Unscrew the center screw 1 e Remove the support 2 e Pry the plug out of the annular buffer at the starter side e Take the screw out of the buffer e Pry the plugs out of the annular buffers at
20. aft locates against the ball bearing Unscrew the hexagon nuts Unscrew the spindle clockwise and take away the service tool Take out the two M5x72 screws Hold the crankshaft steady rotate the spindle counterclockwise to screw the threaded sleeve onto the crankshaft Release the crankshaft Hold the service tool steady and continue turning the spindle until the tool locates against the guide bar mounting face Fit two hexagon nuts on the bar mounting studs and screw them down fingertight e Use a5 mm 3 16 drift to drive the dowel pin into the two halves of the crankcase from the sprocket side 31 4 8 Decompression Valve e Fit screws and tighten them down e Fit the assembly sleeve 1 Remove carburetor box cover alternately in a diagonal pattern to 1124 893 4600 over the clutch see 10 1 11 5 Nm 8 5 Ibf ft end of the crankshaft e Pull off the spark plug boot 1 Note Trim away any excess gasket material in the area of the cylinder mounting face Coat sealing lips of oil seals with grease see 11 2 Apply thin coating of sealant see 11 2 to outside diameter of oil seals Slide the oil seal open side facing the crankcase over the ignition end of the crankshaft Slide the oil seal open side facing e Take out the shroud mounting the crankcase over the assembly screws sleeve Lift away the shroud e Press it home with press sleeve 1 1127 893 2400 Re
21. anchor pin has been removed coat the knur led area of the new pin with Locti te see 11 2 before installation Position the new pin in the bore so that the knurling on the pin meshes with the existing knurling in the bore e Use pliers to grip the pivot pin and pull it out of the crankcase Coat the knurled area of the new pin with Loctite see 11 2 before installation Position the new pin in the bore so that the knurling on the pin meshes with the existing knurling in the bore Carefully drive the pin into the crankcase Important Pin must be driven home at exact right angle e Carefully tap home the pin squarely to obtain dimension a 4 3 4 7 mm 11 64 Important Pin must be driven home at exact right angle Install the cylinder see 4 5 2 Install the chain brake see 3 3 2 13 3 4 Chain Tensioner Remove inner side plate see e Take out the brake washer 3 3 1 e Rotate the spur gear clockwise until the tensioner slide 1 butts against the thrust pad 2 e Take out the retainer 1 e Pull out the spur gear e Take out the screw 2 e Remove the cover plate e Take out the tensioner slide with adjusting screw and thrust pad STIHL 088 e Inspect the teeth on the spur gear and adjusting screw 1 If the teeth are damaged pull off the thrust pad 2 take the adjusting screw out of the tensioner slide 3 and replace both parts Note The a
22. ated with a little oil 1 w Se e Use assembly hook 1 e Pull suction hose and pickup 5910 893 8800 to pull the pickup body out of the crankcase body out of the oil tank Note Avoid stretching the oil hose STIHL 088 43 9 2 Valve 9 3 Spur Gear A valve is installed in the tank wall to keep internal tank pressure equal to atmospheric pressure Cleaning the valve Unscrew the oil filler cap Drain the oil tank Note Collect chain oil in a clean container or dispose of it properly at an approved disposal site e Use a7 mm 9 32 drift to care Remove the clutch see 3 2 fully press in the new valve until it Remove the inner side plate is about 1 0 mm 3 64 below the e Pull the worm with drive spring see 3 3 1 face of the crankcase out of the oil pump and off the crankshaft stub Blow valve clear with com Refit the inner side plate see pressed air from outside to 3 3 2 inside of tank Fit the oil filler cap Flush out the oil tank Fit the inner side plate see 3 3 2 Refit the oil tank filler cap O E 7 NS Replacing the valve e If necessary remove the drive i spring from the worm Unscrew the oil filler cap i Reassemble in the reverse Remove the inner side plate sequence see 3 3 1 e Apply a drift from outside and ca refully drive the vent valve out of the crankcase and remove it from the oil tank STIHL 088 9 4
23. ciency and protection offered against being injured by the rotating chain Contamination with chain oil chips fine particles of abrasion etc and smoothing of the friction surfaces of the brake band and clutch drum impair the coefficient of friction This in turn reduces the frictional forces and thus pro longs the braking time A fatigued or stretched brake spring has the same negative effect Start the engine With the chain brake activated locked open throttle wide for brief period max 3 seconds the chain must not rotate With the chain brake released open throttle wide and activate the brake manually the chain must come to an abrupt stop Note The braking time is in order if deceleration of the saw chain is imperceptible to the eye 12 3 3 4 Brake Spring Anchor Pin Remove the cylinder see 4 5 1 Remove the chain brake see 3 3 1 e Use a suitable punch to drive the anchor pin out of the crankcase in the direction of the arrow Important Do not drive out the pin in the other direction as this would damage the annular bead which was formed in the crankcase bore when the pin was originally installed In such a case neither the new anchor pin nor the brake spring would locate properly Furthermore the crankcase could be damaged in this way and possibly impair correct operation of the chain brake STIHL 088 3 3 5 Hand Guard Pivot Ifthe brake spring
24. ck that cam lever is properly located on face of hand guard bearing boss Secure bell crank with E clip Coat brake band with chain oil STIHL Bioplus see 11 2 to protect it from corrosion and cushion snatching during the first few brake applications Hook the brake spring onto the bell crank Position the brake band behind the lugs on the crankcase Press brake band into slot Coat the mounting screw with Loctite see 11 2 and torque down to 3 0 Nm 2 2 Ibf ft 11 e Coils of brake spring must locate tight against one another in relaxed condition Install a new brake spring if necessary e Check that protective tube is correctly positioned a 20 mm 3 4 b 42 mm 1 5 8 e Attach the brake spring to the bell crank STIHL 088 Use the assembly tool 2 1117 890 0900 to attach the brake spring 1 to the anchor pin Fit cover over the chain brake Fit the side plate Install clutch drum chain sprocket see 3 1 Mount guide bar and chain sprocket cover Tighten sprocket cover nuts to approx 15 20 Nm 11 15 Ibf ft Check operation of chain brake see 3 3 3 3 3 3 Checking Function The chain brake is one of the most important safety devices on the chainsaw Its efficiency is measured in terms of braking time i e the time that elapses between activating the brake and the saw chain coming to a standstill The shorter the braking time the better the effi
25. ct parts and replace if damaged STIHL 088 3 3 2 Assembly e Unhook the spring 2 and take it Lubricate sliding and bearing away points of chain brake with STIHL multipurpose grease or prefer e Pull off the cam lever 3 ably Molykote grease see 11 2 Inspect parts Replace any worn or damaged parts Clean chain brake seat in crank case If the groove of the brake spring anchor pin is worn the anchor e Ease the E clip off the bell crank pin must be replaced see 3 3 4 pivot pin e Carefully ease the hand guard e Push the cam lever 1 onto the 1 and bell crank 2 off the pivot pivot pin pins and lift them away together e Fit the E clip 2 Pull the bell crank out of the hand guard e Remove the E clip 1 e Attach the spring 1 to the pivot pin 2 and cam lever STIHL 088 10 Insert the bell crank in the side of the hand guard so that the short arm of the bell crank points up Position the hand guard 1 against the pivot pin and fit the other side of the hand guard over the housing Position the bell crank 2 against the pivot pin Press the cam lever 3 slightly downward and push the hand guard and bell crank onto their pivot pins Push the metal bushing into the back of the rubber bushing as far as shoulder Press the rubber bushing into the hand guard Fit hand guard mounting screw and tighten to 7 0 Nm 5 2 Ibf ft STIHL 088 e Che
26. djusting screw and spur gear must be replaced together Reverse the above sequence to install the chain tensioner Coat teeth of adjusting screw and spur gear with grease see 11 2 before refitting e Check that O ring is fitted in spur gear and lubricate it with a little oil before installing 14 4 ENGINE 4 1 Exhaust Muffler Spark Arresting Screen Troubleshooting chart see Standard Repairs Troubleshooting handbook Remove the shroud see 4 8 lt gt lt c K Muffler without spark arresting screen e Take out the screws 1 e Remove the cover 2 Fit the cover so that the stub points away from the exhaust port 171RA039 VA e Take out the screws Muffler with spark arresting screen e Remove the spark arresting screen Clean the spark arresting screen or fit a new one 171RA042 VA e Take out the screws 1 e Remove the strap 2 lt gt IS JE S e Ease away the clips 1 e Take out the screws 1 e Remove the retainers 2 e Remove the cover 2 e Remove the muffler 3 STIHL 088 e Remove the exhaust gasket Reassemble in the reverse sequence 4 2 Leakage Test 4 2 1 Preparations Defective oil seals and gaskets or cracks in castings are the usual causes of leaks Such faults allow supplementary air to enter the engine and thus upset the fuel air mixture This makes adjustment of the prescribed idl
27. e 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 STIHL 088 The special servicing tools mentioned in the descriptions are listed in the last chapter 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 e 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 gt Service manuals and all technical information bulletins describing engineering changes are intended exclusively for the use of STIHL servicing dealers They must not be passed to third parties Pointer Direction of movement Servicing and repairs are made considerably easier if the powerhead is mounted to the assembly stand 1 5910 890 3100 This enables the powerhead to be swivelled to the best position for the ongoing repair and leaves both hands free Always use original STIHL replacement parts They can be identified by the STIHL part number the STIHL logo and the STIHL parts symbol amp The symbol may appear a
28. e speed difficult if not impossible Moreover the transition from idle speed to part or full throttle is not smooth Install a new exhaust gasket Remove decompression valve The crankcase can be checked see 4 8 e Attach clip 1 to retainer 2 thoroughly for leaks with the carburetor and crankcase tester and e Install plug 1 1122 025 2200 Tightening torques see 2 6 the vacuum pump and tighten to 14 Nm 10 3 Ibf ft e Check that spark plug 2 is properly tightened down Remove the muffler see 4 1 Remove the carburetor see 10 2 1 Set the piston to top dead center T D C This can be checked through the intake port e Check that sleeve is in position STIHL 088 16 4 2 2 Pressure Test e Push the test flange 1 e Mount the clamp 1 1106 850 4201 into position 0000 890 4400 e Fit sleeves 2 1127 851 8300 e Fit nuts 3 and tighten down firmly e Connect pressure hose of tester 1106 850 2905 to nipple on test flange e Seal the end of the impulse hose with a pointed piece of round stock 3 mm dia or a scriber e Fit the flange 1 1124 850 4205 in position STIHL 088 e Close the vent screw 1 on the rubber bulb Pump air into the crankcase with rubber bulb until the gauge indicates a pressure of 0 6 bar 8 7 psi If this pressure remains constant for at least 20 seconds the crankcase is airtight 17 e However if the i
29. ent based degreasant containing no chlorinated or halogenated hydrocarbons see 11 2 Fit the flywheel in position Fit and tighten down flywheel nut to 45 Nm 33 0 Ibf ft Assembly of the remaining parts is now a reversal of the disassembly sequence e Screw the puller 1 1106 890 4501 into the flywheel e Screw home the thrust bolt until the flywheel is released STIHL 088 36 5 4 Ground Wire Short Circuit Wire 5 5 Contact Spring Remove the filter base see 10 1 Remove the shroud see 4 8 e Pull the ground wire 1 out of the contact spring e Pull the short circuit wire out of the switch shaft e Pull short circuit wire 1 and ground wire 2 out of lower grommet STIHL 088 Remove carburetor box cover see 10 1 Pull short circuit wire 1 and ground wire 2 out of retainer 3 and the upper grommet 4 Pull ground wire out of contact Remove the fan housing spring see 5 4 see 5 1 2 e Use a small screwdriver to ease the contact spring off the lug in the tank housing and use suitable pliers to pull it out of its seat at the same time Install new contact spring Fit the ground wire Fit the carburetor box cover see 10 1 Pull short circuit wire 1 off the tag on the ignition module and ease it out of the retainer 2 Take out the screw Remove the ground wire 3 Pull short circuit and ground wires out of the insulating tube 4
30. er spiked bumper Torque Nm 7 0 7 0 9 0 11 5 7 5 7 5 10 0 7 0 15 0 45 0 14 0 30 0 80 0 25 0 5 5 8 0 8 0 6 0 Use the following procedure when refitting a Plastoform 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 Ibf ft 5 2 5 2 6 6 5 5 5 5 7 5 5 2 3 7 33 0 10 3 22 0 59 0 18 5 4 0 5 9 5 9 Remarks oO lt RW This procedure ensures that the screw engages properly in the existing thread and does not form a new thread and weaken the joint YS rove wH 1 2 3 4 R version only Sealant Hylomar Screw secured with Loctite 242 Screw secured with Loctite 648 Note Use hot air blower hair dryer to release screws secured with adhesive Take special care with polymer components Power screwdriver speed for use in polymer Plastoform screws DG screws STIHL 088 max 600 rpm max 500 rpm 3 CLUTCH CHAIN DRIVE CHAIN BRAKE AND CHAIN TENSIONER 3 1 Clutch Drum Chain Sprocket 145RA006 e Unscrew nuts e Ifa rim sprocket is fitted pull it Important If there are noticeable Remove the chain sprocket cover off wear marks on the inside diameter of the clutch drum check its wall thickness If it is less than 80 of the original wall thickness fit a new clutch drum 143RA004 VA 171RA011 VA e Disengage the chain brake by e
31. ide 57 11 2 Servicing Aids Lubricating grease 2 Standard commercial solvent based degreasant without chlorinated or halogenated hydrocarbons 3 STIHL special lubricant 4 Ignition lead HTR 10 m 33 5 Electrician s repair kit 6 Graphite grease 7 Dirko sealant 100 g 3 5 oz 8 STIHL multipurpose grease 9 Medium strength threadlocking Loctite 242 10 High strength threadlocking Loctite 648 STIHL 088 0781 120 1111 0781 417 1315 0000 930 2251 0000 007 1013 0783 830 2120 0781 120 1109 0786 111 1101 0786 110 0126 Oil seals oil pump drive chain sprocket bearing Cleaning crankshaft stub Bearing bore in rope rotor rewind spring in starter cover Peg on starter pawl Outside diameter of oil seals High voltage output on ignition module Securing screws see 2 6 Securing screws see 2 6 58
32. it spark plug boot over the ignition lead Use suitable pliers to grip the end of the ignition lead inside the spark plug boot and pull it out Weg rs Pinch the hook of the leg spring into the center of the lead i e about 15 mm 5 8 from the end of the lead e Use suitable pliers to grip the leg spring and pull it out of the spark plug boot e Pull the lead back into the boot so that the leg spring locates properly inside it 35 5 3 Flywheel Removing the flywheel Use locking strip to block piston see 3 2 Remove the fan housing see 5 1 2 Rotate the flywheel so that the magnet poles are opposite the ignition module e Use a pointed tool awl or gimlet to e Pull off the flywheel pierce the center of the other end of the ignition lead which screws into the module Slip the insulating hose and grommet onto the lead Pack the high voltage output with STIHL multipurpose grease see 11 2 Important Do not use graphite grease Molykote or silicone insulating paste Screw home the ignition lead Slide the grommet over the high voltage output Install the ignition module see 5 1 2 e Unscrew the flywheel nut Inspect flywheel 1 and magnets 2 If you find any damage e g cracks broken fan blades fit a new flywheel Installing the flywheel Important Clean the stub of the crankshaft and the flywheel hub bore with a standard commercial solv
33. l 50 1 with STIHL 50 1 two stroke engine oil 25 1 with other brand name two stroke air cooled engine oils Standard filter green with wire mesh element for normal operating conditions and winter operation or HD filter special accessory 2 3 Ignition System 2 4 Cutting Attachment STIHL 088 Type Air gap Ignition timing Spark plug suppressed Electrode gap Spark plug thread Length of thread Heat range Guide bars Bar tail Bar lengths Oilomatic chain Chain sprockets Chain speed Chain lubrication Oil delivery rate Oil tank capacity Electronic magneto ignition breakerless with integral trigger unit 0 2 0 3 mm 0 008 0 012 in 2 3 3 3 mm 0 091 0 130 in B TD C at 8 000 rpm Bosch WSR 6F or NGK BPMR7A 0 5 mm 0 02 in M14x1 25 9 5 mm 0 37 in 200 STIHL Rollomatic with nose sprocket STIHL Duromatic with Stellite tipped nose Both types with corrosion resistant finish and induction hardened rails 3002 Rollomatic 53 63 75 90 and 105 cm 21 25 30 35 and 41 in Duromatic 53 63 75 90 105 120 and 150 cm 21 25 30 35 47 59 in 10 26 mm 0 404 Rapid Micro and Rapid Super standard equipment 9 32 mm 3 8 Rapid Micro and Rapid Super as well as 12 7 mm 1 2 Rapid Standard available as options 7 tooth 0 404 rim or spur sprocket standard equipment 8 tooth 3 8 rim and spur sprockets 23 9 m s 78 4 ft sec at 8
34. lone on small parts 2 SPECIFICATIONS 2 1 Engine 2 2 Fuel System STIHL 088 STIHL single cylinder two stroke engine with special impregnated cylinder bore Displacement Bore Stroke Engine power Max torque Max engine speed Main bearings Big end bearing Small end bearing Piston pin diameter Connecting rod length Rewind starter Pawls Reserve pull on rope rotor Starter rope Clutch Diameter Clutch engages at Crankcase leakage test at gauge pressure under vacuum Carburetor Standard setting High speed screw H Low speed screw L Carburetor leakage test at gauge pressure Function of tank vent at gauge pressure under vacuum Fuel tank capacity Octane number Fuel mixture Mix ratio Air filter 121 6 cm 7 42 cu in 60 mm 2 35 in 43 mm 1 69 in 6 3 kW 8 6 bhp 8 0 Nm 5 9 Ib ft at 6 000 rpm 12 000 rpm Two deep groove ball bearings Needle cage Needle cage 13 mm 0 51 in 75 mm 2 95 in ElastoStart Two pawl system min 2 turns 4 5 mm 0 18 in dia 1000 mm 39 4 in long Centrifugal clutch without linings 87 mm 3 4 in 3 200 rpm 0 6 bar 8 7 psi 0 4 bar 5 8 psi Diaphragm carburetor Open approx 1 turn Open approx 1 turn 0 8 bar 11 6 psi lt 0 5 bar 7 25 psi lt 0 1 bar 1 45 psi 1 3 2 75 US pt min 90 RON US CAN pump octane min 87 unleaded Regular brand name gasoline and two stroke engine oi
35. mference of shaft seal Slip the shaft seal open side facing the pump housing over the worm e Press home with press plate 1 1124 893 5100 46 10 FUEL SYSTEM 10 1 Air Filter Dirty and clogged air filters reduce engine power increase fuel con sumption and make starting more difficult The air filter should always be cleaned when engine power begins to drop off 171RA197 VA e Unscrew the twist lock 1 e Remove the carburetor box cover 2 lt gt o r a lt ira 5 7 e Remove the air filter STIHL 088 Wash the filter in a fresh non flammable cleaning solution e g warm soapy water and if possi ble blow out with compressed air Soften encrusted dirt by soaking the filter in cleaning solution Always replace a damaged air filter 171RA200 VA e Unscrew the collar nuts 1 e Pull off the flange 2 e Remove the filter base lt gt a lt x E HD filter special accessory e Pull off the felt prefilter Wash prefilter mesh in a fresh non flammable cleaning solution e g warm soapy water and if possible blow out with compressed air Soften encrusted dirt by soaking element in cleaning solution Always replace a damaged prefilter Impregnate filter element with special filter oil see 11 2 Fit felt prefilter over the HD filter lt gt A N A lt c A e The word TOP must face up Reas
36. minal nut make sure that it is properly tightened down Install decompression valve see 4 8 Install clutch drum chain sprocket see 3 1 e Unscrew the spark plug e Push the locking strip e Fit cover washer so that TOP 0000 893 5903 into the cylinder faces outward STIHL 088 3 3 Chain Brake 3 3 1 Disassembly 171RA012 VA lt gt y lt c 6 Remove clutch drum chain e Take out the brake band Replace the brake band if sprocket fastening screw see 3 1 there are noticeable signs of wear large areas on inside diameter e Take out the screw 1 and or parts of outside diameter and e Remove the side plate 2 its remaining thickness is lt 0 6 mm 0 024 Important Thickness of brake band must not be less at any point e Ifthe brake band is still service able use No 120 emery paper or emery cloth grain size approx 120um to clean and roughen its entire friction surface inside diameter 171RA013 VA 171RA016 VA Relieve tension of brake spring e Lever the brake band out of the by pushing the hand guard crankcase forward e Take out the screws 1 e Lift away the cover 2 e Carefully pry the brake spring 1 e Remove the brake band from the e Take out the screw 1 off the anchor pin and unhook it lugs 1 on the crankcase from the bell crank 2 e Remove the rubber bushing 2 e Unhook the brake band from the bell crank 2 Inspe
37. move the assembly sleeve Wait about one minute then turn the crankshaft several times lt gt Assembly of the remaining parts is a __ reversal of the disassembly sequence Remove the grommet 1 e Press it fully home with press sleeve 1 1127 893 2400 Unscrew the decompression Note The press surface must be flat valve 2 and free from burrs STIHL 088 32 e Fit new decompression valve and torque down to 14 Nm 10 3 Ibf ft e Fit the grommet and check that it is properly seated e Fit the shroud and make sure the ignition lead is correctly positioned in the shroud recess Reassemble all other parts in the reverse sequence STIHL 088 5 IGNITION SYSTEM Warning Exercise extreme caution when carrying out maintenance and repair work on the ignition system The high voltages which occur can cause serious or even fatal accidents Troubleshooting on the ignition system should always begin at the spark plug See Standard Repairs Troubleshooting handbook lt gt c K Note The electronic breakerless ignition system basically consists of an ignition module 1 and flywheel 2 and is easily accessible 5 1 Ignition Module lt Q lt The ignition module accommodates all the components required to control ignition timing There are three electrical connections on the coil body 1 the high voltage output 1 2 the ground wire 2 3 the connector
38. ndicated pressure drops the leak must be located and the faulty part replaced Note To find the leak coat the suspect area with oil and pressurize the crankcase again Bubbles will appear if a leak exists Carry out the vacuum test see 4 2 3 After finishing the test open the vent screw and disconnect the hose Remove the test flange Install the carburetor see 10 2 1 Remove the test flange with clamp Install the muffler see 4 1 Unscrew the plug from the cylinder Install decompression valve see 4 8 STIHL 088 4 2 3 Vacuum Test Oil seals tend to fail when subjected to a vacuum i e the sealing lip lifts away from the crankshaft during the piston s induction stroke because there is no internal counterpressure An additional test can be carried out with the vacuum pump to detect this kind of fault The preparations for this test are the same as for the pressure test see 4 2 2 e Connect suction hose of vacuum pump 0000 850 3501 to test flange nipple he a S e Close the vent screw 1 on the pump e Operate lever 2 until pressure gauge 3 indicates a vacuum of 0 4 bar 5 8 psi Note f the vacuum reading remains constant or rises to no more than 0 3 bar 4 25 psi within 20 seconds it can be assumed that the oil seals are in good condition However if the pressure continues to rise reduced vacuum in the crankcase the oil seals must be
39. ndle 1 of the service tool clockwise until the crankshaft is pressed out of the ball bearing The two halves of the crankcase separate during this process Remove service tool AS Remove crankcase gasket Unscrew spindle of service tool ZS a little left hand thread STIHL 088 e Fit service tool ZS 1 5910 007 2220 against starter side of crankcase so that number 9 2 on the plate is at the bottom Note Cylinder flange upright Insert four M5x72 screws 9022 341 1190 in the holes and tighten them down against the drilled plate e Turn spindle 1 counterclockwise until the crankshaft is pushed out of the ball bearing The crankshaft 1 connecting rod 2 and needle bearing form an inseparable unit This means that the crankshaft must always be replaced as a complete unit When fitting a replacement crankshaft always install new oil seals and ball bearings e Pry the oil seal out of the ball bearing at the clutch side 26 Inspect both halves of the crankcase for cracks and replace if necessary Note The crankcase must be replaced as a complete unit even if only one half is damaged All other parts which are still serviceable can then be transferred to the new crankcase If only the ball bearings have to be replaced remove all rubber and plastic components first i e oil suction hose stop buffer and annular buffers Carry out the following operations for this purpose e
40. of the grooves in the pistons STIHL 088 e Inspect piston rings and replace if necessary see 4 6 Push the assembly drift small diameter first through the piston and small end needle cage and line up the piston 21 e Fit the piston pin 1 on the e Place new cylinder gasket in e Push the manifold onto the assembly drift 2 and slide it into position intake port the piston the pin slides home easily if the piston is heated e Note installed position of manifold s ay e Apply the installing tool 1 e Lubricate the piston and piston Push the hose clamp over the 5910 890 2212 to the piston boss rings with oil and place the piston manifold The screw head must hold the piston steady center the 1 on the wooden assembly block point to the right tool shank exactly and press home 2 1108 893 4800 until the snap ring slips into the e Tighten the hose clamp Ends of groove clamp must point down to the right at angle a of 45 degrees Note For instructions on how to use installing tool see Standard Repairs Note Tighten the screw until the gap Troubleshooting handbook b between the two ends of the hose clamp is 6 5 7 mm 0 25 0 27 in e Install the new piston rings in the grooves so that the radii at the ring gap face upward and meet at the fixing pin STIHL 088 22 Note The manifold flange is thus pulled through the tank housing intake opening without damaging the manifold
41. or leakage test Fitting piston Compressing piston rings For leakage test Testing carburetor and crankcase for leaks Testing crankcase for leaks Removing oil seals Installing oil seal starter side clutch side Protecting oil seal at clutch side Fitting piston pin Fitting hookless snap rings in piston Removing bar mounting studs Setting air gap between ignition module and flywheel Removing pickup bodies Holding saw for repairs 5910 890 2005 Attaching the brake spring Removing crankshaft clutch side Installing crankshaft Removing crankshaft starter side Pulling crankcase together 0 5 to 18 Nm 0 325 to 13 5 Ibf ft 6 to 80 Nm 4 5 to 60 Ibf ft NO AaN YS vewr Assembling oil pump Installing oil pump shaft seal 56 34 T handle screwdriver QI T27x150 35 Crimping tool 36 Puller 37 Socket 17 mm 38 Socket 21 mm 39 Screwdriver bit T27x125 40 Press arbor 41 Press arbor Remarks 5910 890 2400 5910 890 8210 1106 893 4501 5910 893 5610 5910 893 5615 0812 542 2104 1124 893 7200 1119 893 2401 1 Always use torque wrench to tighten P screws 2 Wrench has optical acoustic signal 3 On P screws use for releasing only STIHL 088 Application Rem For all IS screws 3 Attaching connectors to electrical wires Removing flywheel Flywheel nut Clutch IS screws Removing and installing ball bearing clutch side Removing and installing ball bearing starter s
42. r Oil Pump Removing and Installing Servicing 33 33 34 34 35 36 37 37 38 38 38 39 40 41 41 42 43 43 44 45 45 45 10 Fuel System 10 1 Air Filter 10 2 Carburetor 10 2 1 Removing and Installing 10 2 2 Leakage Test 10 2 3 Adjustment 10 3 Tank Vent 10 4 Pickup Body 10 5 Fuel Hoses 10 6 Tank Housing 11 Special Servicing Tools and Aids 11 1 Special Servicing Tools 11 2 Servicing Aids STIHL 1996 Andreas Stihl Waiblingen 47 47 48 48 49 50 51 51 53 56 56 1 INTRODUCTION This service manual contains detailed descriptions of all the repair and servicing procedures specific to this series of chainsaws There are separate handbooks for servicing procedures on standardized parts and assemblies that are installed in several STIHL power tool models Reference is made to these handbooks in the appropriate chapters of this manual 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 Always use the latest edition of the parts list to determine the part numbers of any replacement parts required Microfilmed parts list are always more up to date than printed lists A fault on the machine may have several causes Consult the troubleshooting charts for all assemblies in the Standard Repairs Troubleshooting handbook Refer to th
43. retor or the fuel supply system always check and clean the tank vent Equalization of pressure from the outside inwards takes place via the sintered filter 1 and the valve 2 Note The sintered filter helps prevent dirt entering the valve or the tank The cap 3 protects the sintered filter from damage and contamination STIHL 088 Equalization of pressure from the inside outwards takes place via the bore in the tank the valve and sintered filter Remove the carburetor box cover see 10 1 e Pull off the cap e Pull the sintered filter 1 and valve 2 out of the tank 10 4 Pickup Body 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 Important 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 Cleaning the fuel tank e Unscrew the filler cap and drain the tank Pour a small amount of clean gasoline into the tank Close the tank and shake the saw vigorously Open the tank again and drain it Note Dispose of old fuel at approved disposal site 51 10 5 Fuel Hoses Outer fuel hose Inner fuel hose
44. semble in the reverse sequence 47 10 2 Carburetor 10 2 1 Removing and Installing Remove the filter base see 10 1 e Disconnect the impulse hose 1 and fuel hose 2 e Pull the grommet off the adjusting screws and out of the housing e Pull off the sleeve 3 Remove the handle molding e Lift away the carburetor see 8 2 Reassemble in the reverse e Disconnect the throttle rod from sequence the double lever lt gt 2 c 171 A048 VA e Disconnect choke rod from the e Before installing the carburetor choke lever check that sleeve is in position STIHL 088 After pushing carburetor into position check that elbow con nectors are properly seated in impulse hose 1 and fuel hose 2 48 10 2 2 Leakage Test The carburetor can be tested for leaks with the carburetor and crankcase tester 1106 850 2905 Remove filter base see 10 1 e Push the fuel line 1 1110 141 8600 onto the nipple 2 0000 855 9200 e Pull off the fuel hose STIHL 088 e After completing the test open the vent screw and pull the fuel line off the elbow connector e Install the filter base see 10 1 e Push the fuel line with nipple onto the carburetor s elbow connector Push the nipple into the tester s pressure hose Close the vent screw 1 on the rubber bulb 2 and pump air into the carburetor until the pressure gauge 3 shows a reading of approx 0 4 bar
45. studs carried out very quickly because the bearing absorbs heat immediately and begins to expand e Check that dowel pin is in position If necessary drive dowel pin into new crankcase STIHL 088 If it is not possible to heat the crankcase use the press arbor 1 1124 893 7200 to press in the ball bearing as far as stop 28 Heat area of bearing seat on starter side of crankcase to approx 150 C 300 F e Place ball bearing in position closed side up and push it home by hand as far as stop Note This operation must be carried out very quickly because the bearing absorbs heat immediately and begins to expand e After the crankcase has cooled down push the annular buffer into position until its annular groove 1 engages the edge of the housing 2 e Place filler cap s cord 1 in the groove 2 and pull it forward Push the two annular buffers tapered end first into position until their annular grooves 1 engage the edge of the housing 2 e Push the oil suction hose into the crankcase bore e If itis not possible to heat the crankcase use the press arbor 1 1124 893 7200 to press in the ball bearing as far as stop STIHL 088 After the crankcase has cooled down push the stop buffer into guide until its lugs are behind the edge of the housing Use a blunt tool to push the oil suction hose into the bore so that its tab locates in the recesss at the top lef
46. t 29 e Screw the spindle fully into service tool ZS 2 and then screw the threaded sleeve 1 5910 893 2421 onto the spindle as far as it will go Lubricate tapered crankshaft stub with oil e Hold the spindle steady and turn e Fit anew gasket on the clutch the service tool counterclockwise side of the crankcase until the drilled plate butts against the crankcase e Place tapered crankshaft stub in ball bearing at starter side of crankcase e Turn the spindle clockwise the Lubricate straight crankshaft until the crankshaft locates stub with oil against the ball bearing e Position crankshaft stub in ball Important The connecting rod must bearing point toward the cylinder flange while the crankshaft is being installed e Apply threaded sleeve 1 to thread 2 on crankshaft stub and screw it on STIHL 088 Release the spindle by turning it counterclockwise and then hold the crankshaft steady and unscrew the service tool counterclockwise 30 To prevent the crankcase and gasket twisting fit M5x72 screws from service tool ZS in two crankcase holes as far as stop Screw the spindle fully into service tool AS by turning it clockwise 145RA15 e Screw threaded sleeve 1 5910 893 2408 onto the spindle as far as it will go left hand thread STIHL 088 Push the threaded sleeve over the crankshaft stub e Turn the spindle counterclockwise until the cranksh
47. ten them down yet Important A washer must be fitted under each screw head Note Secure the ground wire with the upper mounting screw e Take out the screws Remove the ignition module Remove the ignition lead see 5 2 e Rotate the flywheel until the magnets are between the arms of the ignition module 34 e Slide the setting gauge 1 Important Tighten the top screw first 1111 890 6400 between the arms of the ignition module and the raised edge of the flywheel Press the ignition module against the setting gauge and tighten down the mounting screws to 9 0 Nm 6 6 Ibf ft Remove the setting gauge and use a feeler gauge to check the air gap It should be 0 20 mm 0 008 Reconnect the short circuit wire Fit the fan housing tighten screws to 7 0 Nm 5 2 Ibf ft Install the shroud see 4 8 Fit the carburetor box cover see 10 1 STIHL 088 5 2 Spark Plug Boot Ignition Lead Remove the ignition module see 5 1 2 e Pull the grommet 1 off the high voltage output 2 e Unscrew the lead 3 from the contact pin and pull it out of the ignition module e Pull grommet and insulating tube 4 off the ignition lead Unhook the leg spring from the ignition lead Slip the spark plug boot off the ignition lead Cut new ignition lead to length see parts list or cut to same length as old lead Coat end of the ignition lead about 20 mm 3 4 with oil F
48. throttle rod out of the e Press the interlock lever 1 down throttle trigger e Pull the throttle trigger 2 up and move the Master Control lever 3 to Choke STIHL 088 171AA176 VA 9 CHAIN LUBRICATION 9 1 Pickup Body Suction Hose Impurities gradually clog the fine pores of the filter with tiny particles of dirt This prevents the oil pump from supplying sufficient oil to the bar and chain In the event of problems with the oil supply system first check the oil tank and the pickup body Clean the oil tank if necessary Troubleshooting chart see Standard Repairs Troubleshooting handbook e Pull the pickup body out of the oil e Pull the pickup body 1 off the suction hose suction hose 2 Wash the pickup body in white Reassemble in the reverse spirit and if possible blow out with sequence compressed air Always replace a damaged pickup Pickup body body Flush out the oil tank Assembly is a reversal of the disassembly sequence e Unscrew oil filler cap and drain Suction hose Insert suction hose in bore the oil tank Remove the oil pump see 9 4 1 e Use a blunt tool to push the end of Note Collect chain oil in a clean the suction hose into the container or dispose of properly Use pliers to grip the tab of the oil crankcase so that the tab locates hose and pull it out of the bore it its seat at the bottom right This operation is easier if the bead of the hose is lubric
49. tub with standard commercial solvent based degreasant containing no chlorinated or halogenated hydrocarbons see 11 2 Lubricate sealing lips of oil seal with grease see 11 2 Apply thin coat of sealant see 11 2 to outside diameter of oil seal e Apply puller 1 5910 890 4400 e Use the press sleeve 1 with No 3 1 jaws 1127 893 2400 to install the oil 0000 893 3706 seal STIHL 088 19 e Slip assembly sleeve 1 1124 893 4600 over the crank shaft stub Push the oil seal open side facing the crankcase over the assembly sleeve Press oil seal home with press sleeve 1 1127 893 2400 Remove the assembly sleeve Wait about one minute then turn the crankshaft several times Install the spur gear see 9 3 STIHL 088 4 4 Exposing the Cylinder 4 5 4 5 1 Cylinder and Piston Removal Always check and if necessary repair the fuel system carburetor air filter and ignition system before looking for faults on the engine Troubleshooting chart see Standard Repairs Trouble shooting handbook Remove the muffler see 4 1 Remove the carburetor see 10 2 1 i Preparations see 4 4 Remove decompression valve see 4 8 e Unscrew the four cylinder base screws through the holes in the cylinder Carefully lift the cylinder up and at the same time push the manifold through the tank housing opening e Take the sleeve out of the e manifold Caution Do
50. x12 Oil pump crankcase front top 3 5 2 6 1 Spline screw IS M4x12 Brake band crankcase 3 0 2 2 2 Spline screw IS M4x12 Oil pump cover crankcase 3 0 2 2 Spline screw IS M4x12 Exhaust cover muffler 4 0 3 0 Spline screw IS M4x12 Spur gear cover crankcase 3 0 2 2 Collar nut M5 Shroud cylinder 7 0 5 2 Collar nut M5 Tank housing carburetor flange 5 0 3 7 Spline screw IS M5x12 Top left annular buffer plate crankcase 9 0 6 6 2 Spline screw IS M5x16 Support muffler 10 0 7 5 Spline screw IS M5x20 Shroud crankcase 7 0 5 2 STIHL 088 Fastener Spline screw Screw assembly Spline screw Spline screw Nut Spline screw Spline screw Spline screw Spline screw Spline screw Nut Plastoform screw Plastoform screw Plastoform screw Nut Thread size IS M5x20 IS M5x35 IS M5x25 IS M5x25 M6 IS M6x18 IS M6x18 IS M5x16 IS M6x40 IS M6x30 M10x1 M10x1 M 10x27 M14x1 M 14x1 25 IS P6x19 IS P6x21 5 IS P6x32 5 1 8 M5 For component Fan housing crankcase Hand guard fan housing crankcase Ignition module crankcase Crankcase Spiked bumper chain sprocket cover Spiked bumper crankcase bottom Spiked bumper crankcase top Support crankcase Annular buffer top left tank housing Cylinder crankcase Flywheel crankshaft Decompression valve Bar mounting stud Clutch carrier crankshaft Spark plug Annular buffer bottom tank housing Front handle bottom tank housing Front handle right stiffener tank housing Chain catch
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