Stihl 029, 039, Service Manual

Page 1: ...publication of this service manual Service manuals and technical information bulletins describing engineering changes are intended exclusively for the use of STIHL servicing dealers and staff and mus...

Page 2: ...the Bellows 72 Rewind Spring 47 11 6 7 Foam Filter 3 Clutch Chain Drive 6 5 Tensioning the Polymer Sintered Filter 72 Chain Brake and Rewind Spring 47 11 6 8 Removing and Installing Chain Tensioner 14...

Page 3: ...forged Crankshaft bearings 2 ball bearings 2 ball bearings Crankpin dia 14 4 mm 0 55 in 14 4 mm 0 55 in Big end bearing Needle cage Needle cage Conrod length 58 mm 2 28 in 58 mm 2 28 in Piston pin dia...

Page 4: ...e and brand name two stroke engine oil Mix ratio 50 1 with Stihl two stroke engine oil 25 1 with other brand name two stroke brand name air cooled engine oils Air filter Prefilter coarse filter bisect...

Page 5: ...d reciprocating oil pump no feed at idle speed Additional manual oil flow control Oil feed rate adjustable 6 15 cm min 0 2 0 5 fl oz min at 10 000 r p m Oil tank capacity 0 33 L 0 7 US pt 1 5 Special...

Page 6: ...6 Spline screw IS DG5x24 Hand guard I h with sleeve 3 5 2 6 Spline screw IS DG5x24 Fan housing engine housing 3 5 2 6 Spline screw IS DG5x24 Buffer front handle 3 5 2 6 Spline screw IS DG5x24 Buffer e...

Page 7: ...ainer Clutch shoes and carrier Fit new clutch worn Chain sprocket wears Chain not properly Tension chain as specified rapidly tensioned Chain wears rapidly Chain not properly Tension chain as specifie...

Page 8: ...engine pan Engine pan damaged cracks Replace engine pan Engine does not deliver full Secondary air seepage through Mount manifold correctly or power or runs erratically poorly mounted or faulty repla...

Page 9: ...heel appear to be in good condition Fit new spark plug Is air gap correct Adjust air gap 0 15 0 3 mm Is spark test positive Insert screwdriver in place of spark plug in spark plug terminal and hold ab...

Page 10: ...pulled out Guide peg on pawl or pawl Fit new pawls almost without resistance itself worn crankshaft does not turn Spring clip fatigued Fit new spring clip Starter rope is difficult to Starter mechani...

Page 11: ...ash intake hose and pickup strainer clogged or intake body strainer in white spirit hose ruptured and blow out with compressed air replace if necessary Valve in oil tank blocked Clean or replace valve...

Page 12: ...high Set inlet control lever flush relative to design position with bottom of metering chamber Poor acceleration Idle jet too lean Back off low speed adjusting screw slightly see Carburetor Adjustmen...

Page 13: ...completely closed Small plastic plate in valve Clean or renew valve jet jet does not close Engine speed drops quickly under Air filter plugged Clean air filter load low power Tank vent faulty Clean o...

Page 14: ...and remove the sprocket cover clutch drum or chain sprocket Replace the needle cage or wash it in clean white spirit and lubricate Disengage the chain brake by Remove the spur sprocket or rim with ST...

Page 15: ...king strip into the Remove the clutch drum or chain clutch spark plug hole so that TOP or sprocket see 3 1 OBEN is facing upward Troubleshooting chart see 2 1 Unscrew the clutch from the Important To...

Page 16: ...off the Slip the retainers onto the clutch Attach one end of each spring to carrier shoes so that the narrow side is the clutch shoes by hand next to the series number e g Pull the retainers off the...

Page 17: ...3 1 spring from the anchor pin 37 Ibf ft Engage the chain brake Ease the brake band out of its Install clutch drum or spur seat in the engine housing sprocket see 3 1 Remove the upper bumper strip fr...

Page 18: ...e the brake band from the Pry the E clip off the bell crank Remove washer from bell crank retaining lug and disconnect it pivot pin pivot pin from the bell crank Remove the link strap from the Careful...

Page 19: ...pring Clean all disassembled parts in white spirit Replace any worn or damaged parts Push the cam lever onto the pivot Position bearing boss of hand pin and secure it with the E clip guard against the...

Page 20: ...e 12 2 Do not and tighten to 3 5 Nm 2 6 Ibf ft Position the link on the hand lubricate the brake band guard pivot pin and slide it down Fit cover for brake band until it engages the groove on the Atta...

Page 21: ...coversion from front to side chain tensioner it is necessary to drill a hole in the sprocket cover to take the peg of the spur gear see dimensions in illustration Reverse the above sequence to install...

Page 22: ...the teeth are damaged replace both Fit the collar stud and torque it parts down to 16 Nm 11 8 Ibf ft Note The collar stud next to the Reverse the above sequence to chain sprocket is installed with ins...

Page 23: ...piston crankshaft and engine pan Troubleshooting chart see 2 2 Unscrew flanged locknuts from muffler Remove muffler together with cover 4 ENGINE 4 1 Removing and Refitting Exhaust Muffler Remove the...

Page 24: ...g screws Top 1 Sealing plate 0000 855 8106 2 Flange 1123 855 4200 3 Sleeves 1127 851 8300 Bottom Sealing plate between mounting screws 4 2 Leakage Testing the Engine Top Carburetor and crankcase teste...

Page 25: ...t the piston to top dead center T D C This can be checked through the inlet port Connect tester s pressure hose to nipple on test flange Make sure the spark plug is properly tightened down before star...

Page 26: ...is a leak in the oiled area Carry out the vacuum test see 4 2 3 After finishing the tests open the vent screw and disconnect the hose Oil seals tend to fail when subjected to a vacuum i e the sealing...

Page 27: ...e replaced even if no leaks were detected in the pressure test Remove the test flange and refit the carburetor see 11 2 Remove the flange and sealing plate Refit the muffler see 4 1 Note If oil seals...

Page 28: ...al Slip the assembly sleeve 1122 893 4600 over the end of the crankshaft Position oil seal so that the clamping ring points up Use the press sleeve to press home the oil seal as far as stop Note Remov...

Page 29: ...ition lead from the retainer and groove on the cover Take out the cover mounting screws and lift the cover away Remove the ground wire fastening screw from the cylinder Remove the collar stud next to...

Page 30: ...g screws 2 3 and 5 and torque them down to 11 Nm 8 Ibf ft Tighten down mounting screw 1 to 11 Nm 8 Ibf ft Push ignition lead into groove and retainer on cover Push the tank vent into the hole in the c...

Page 31: ...et at the fixing pin in the piston groove when the rings are compressed Note The clamping strap can only be used with cylinders whose inner contour is the same as that shown in the illustration above...

Page 32: ...see 12 2 Position piston with clamping strap in cylinder so that the channel sections on the clamping strap rest on the lands in the cylinder Carefully push the piston into the cylinder Open the clamp...

Page 33: ...boss Note Use special installing tool 5910 890 2210 to fit the snap ring Top Needle cage in small end Bottom 1 Installing tool 5910 890 2210 2 Sleeve Top Pushing out piston pin Bottom Piston rings 1...

Page 34: ...t face of the tool s shank Stand the installing tool sleeve downward on a flat surface wooden board and press vertically downwards until the sleeve butts against the tool s shoulder Owing to the speci...

Page 35: ...bly drift and slide it into the piston the piston pin slides home easily when the piston is hot Use the installing tool 5910 890 2210 to fit the snap ring in the piston boss Note The snap ring must be...

Page 36: ...her parts is a reversal of the disassembly sequence Remove the piston see 4 6 Pull both oil seals off the crank shaft stubs Pull both ball bearings off the crankshaft stubs Note that closed side of ba...

Page 37: ...f the electrodes are badly eroded Troubleshooting on the ignition system should always begin at the spark plug In the event of starting difficulties low engine power misfiring etc unscrew the spark pl...

Page 38: ...ire will cause a short circuit to ground In this case the engine with either not start or only run erratically Installing the spark plug Clean the spark plug seat and inspect the sealing ring to make...

Page 39: ...hat wiring and stop switch are in good condition Remove handle housing see 8 1 1 Pull terminal off the spark plug Remove the ignition lead from the retainer and groove on the cover Pull the short circ...

Page 40: ...on module in position fit screws but do not tighten down yet Important Secure ground wire with upper screw and fit a washer on the lower screw Slide the setting gauge between the arms of the ignition...

Page 41: ...p the leg spring and pull it out of the spark plug terminal Unhook the leg spring from the ignition lead and slip the spark plug terminal and dust seal off the lead Slip the dust seal over the ignitio...

Page 42: ...s old lead Reassembly is a reversal of the disassembly sequence Note Use a pointed tool awl or gimlet to pierce the center of the other end of the ignition lead which screws into the module Note Befor...

Page 43: ...taining no CFCs Fit the flywheel and tighten mounting nut to 27 5 Nm 20 Ibf ft Assembly of the remaining parts is now a reversal of the disassembly sequence Note If the flywheel cannot be removed by h...

Page 44: ...ll the ground wire terminal off the contact spring Ease the contact spring out of its seat in the handle housing Installation is a reversal of the removal sequence Pull the short circuit and ground wi...

Page 45: ...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 12 2 before instal...

Page 46: ...tion of starter rope in rope rotor Bottom Starter rope secured in rope rotor with knot Installing the rope rotor Lubricate guide peg on pawl with graphite grease see 12 2 and then fit the pawl Coat th...

Page 47: ...on If the rewind spring has popped out refit it as follows Position anchor loop about 20 mm 3 4 from the edge of the spring housing Refit the rewind spring in the spring housing in the counter clockwi...

Page 48: ...ed by the starter rope being pulled sideways The wall of the guide bush eventually wears through becomes loose and has to be replaced Remove the fan housing Remove the rope rotor see 6 2 take off the...

Page 49: ...ver the edge of the housing Assembly is now a reversal of the disassembly sequence Push the annular buffer into the front handle from inside until its groove engages over the housing rib Push the lowe...

Page 50: ...se sequence Remove the front handle see 8 1 Remove the carburetor see 11 2 Slip the washer off the mounting studs and take the sleeve out of the manifold Pull the short circuit wire s con nector sleev...

Page 51: ...buffer on the hand guard Push the annular buffer out of the engine housing Pull the handle housing slightly forward and push the manifold through the handle housing opening at the same time Ease the g...

Page 52: ...ani fold and pull the ends of the string outward at the same time The manifold flange is pulled through the handle housing intake opening without being damaged Note Pay special attention to the follow...

Page 53: ...e choke shutter open CHOKE cold start starting throttle choke shutter closed Remove the carburetor box cover see 11 1 Set the Master Control to CHOKE Take the short circuit wire out of its seat on the...

Page 54: ...orsion spring Position the torsion spring on the throttle trigger long leg of spring must face upward Fit the throttle trigger so that the seat for the throttle rod points up ward Push the cylindrical...

Page 55: ...suction hose off the nipple on the oil pump Pull the suction hose out of the engine housing Pull the suction hose with pickup body out of the housing Pull the pickup body out of the hose Use side cut...

Page 56: ...ff the worm Push the suction hose off the nipple on the oil pump A valve is installed in the tank wall to keep internal tank pressure equal to atmospheric pressure Drain the oil tank Use a 7 mm 9 32 d...

Page 57: ...he oil pump see 10 3 Swing the elbow connector to one side and pull it out of the housing Remove the O ring from the elbow connector Use a 2 mm 5 64 dia drift to drive out the spring pin Pull the cont...

Page 58: ...ress down the interlock lever and move Master Control down to cold start position CHOKE Turn twist lock on carburetor box cover one quarter turn counter clockwise and take away the cover Clean away an...

Page 59: ...he throttle shaft Remove the grommet from the adjusting screws and pull it out of the handle housing Pull the carburetor off the studs and pry the fuel hose off the elbow connector at the same time In...

Page 60: ...he rubber bulb and pump air into the carburetor until the pressure gauge shows a reading of approx 0 4 bar 5 8 psi If this pressure remains constant the carburetor is airtight However if it drops ther...

Page 61: ...out the screws of the metering chamber end cover and lift away the cover Remove the metering diaphragm and gasket from the carburetor body or the cover Carefully separate the diaphragm and gasket Not...

Page 62: ...djusting screws Note If there is an annular inden tation on the sealing cone of the inlet needle it will be necessary to replace the inlet needle because it will no longer seal properly This is indica...

Page 63: ...ng When fitting the valve jet make sure it is exactly vertical in the bore Press it home until it is flush with the bottom of the metering chamber Fit the inlet needle and the helical spring in their...

Page 64: ...djusting screws Carry out leakage test before installing the carburetor see 11 3 Removing the throttle shaft Note For machines with automatic choke see 11 6 10 Fit the gasket metering dia phragm and e...

Page 65: ...emoving choke shaft Note For machines with automatic choke see 11 6 10 Unscrew choke shutter fastening screw Remove the choke shutter Pry the E clip off the end of the choke shaft and withdraw the sha...

Page 66: ...ng screw backed off 1 full turn If the carburetor has to be adjusted from scratch first carry out the standard setting to obtain a starting point for fine tuning If no tachometer is available do not t...

Page 67: ...crew LA counterclockwise until the chain stops running and then turn about another quarter turn in the same direction Erratic idling behavior poor acceleration Idle setting too lean Turn the low speed...

Page 68: ...m the carburetor box via a foam filter a polymer sintered filter a hose and control valve The pressurizing process is ac companied by a low whistling noise The polymer sintered filter and foam filter...

Page 69: ...11 6 4 Adjust carburetor see 11 5 Troubleshooting see 2 3 and 2 6 Start with automatic choke Check automatic choke see 11 6 3 Machine is in order Start machine in normal way no yes no yes yes yes no...

Page 70: ...is fully extended It must not move to the fully open position Control valve temperature below 5 C 3 F Choke shutter must not move while the starter rope is pulled out to its full length Remove the ai...

Page 71: ...Push tester s pressure hose onto the nipple Note Leave the cylinder connector open Pull out pump piston several times until pressure gauge shows a vacuum of 0 4 bar 5 8 psi Note Vacuum must not drop m...

Page 72: ...The bellows can be checked for leaks with carburetor and crank case tester The following test is carried out with the bellows removed from the machine but it can also be performed with the bellows in...

Page 73: ...y in position so that the pressure used to install the levers is transmitted to the carburetor body via a short part of the shaft and the retaining ring This procedure ensures that the shaft is not lo...

Page 74: ...l crank G Rotate bell crank counterclock wise until its right arm butts against the pin on lever B With the bell crank in this posi tion carefully press it on to the choke shaft Important Take care no...

Page 75: ...ant The choke shutter must be held open for the next two operations Fit lever H on the throttle shaft and rotate it counterclockwise against the pin on lever A Press lever H on to the throttle shaft T...

Page 76: ...er see 11 4 Pry the E clip off the choke shaft and then withdraw the choke shaft Remove the torsion springs and choke lever from the choke shaft Attach bent end of torsion spring to lug on lever H Pus...

Page 77: ...ws and lift away the cover Clean the cylinder and the area around the control valve Ease the clip away from both sides of the cylinder Remove the control valve from the cylinder Take the O ring out of...

Page 78: ...ates behind the handle housing Line up the bellows so that its nipple points upward Install the carburetor see 11 6 8 Note Lubricate new O ring with a little oil and fit it in the hole in the cylinder...

Page 79: ...ews as shown in the drawing Fit the tank vent on the nipple and then push it into its seat in the cover The diaphragm pump draws fuel out of the tank and into the carburetor via the fuel hose Any impu...

Page 80: ...ting screw from the chain catcher and take away the chain catcher Removing the suction hose Remove the handle housing see 8 1 1 Pull off the pickup body Pry the suction hose out of the tank Remove the...

Page 81: ...f the housing Remove the tank vent from the nipple on the tank housing Assembly is a reversal of the disassembly sequence Note After assembly set the air gap between the ignition module and flywheel s...

Page 82: ...0300 5910 890 0310 0812 542 2104 5910 893 8800 5910 890 2210 5910 890 2800 0000 890 2201 1117 890 0900 5910 890 2400 5910 893 0501 5910 850 3100 5910 890 3100 1127 893 2400 1122 893 4600 Application...

Page 83: ...ipurpose grease Part No 0781 120 1111 0786 111 1109 0786 110 0119 0781 417 1315 0000 930 2251 0000 007 1013 0783 830 2120 0781 120 1109 Application Oil seals oil pump drive chain sprocket bearing Thro...