Stihl MS 271, Manual

Page 1: ...STIH STIHL MS 271 291 2010 06...

Page 2: ...ton Rings 44 7 Ignition System 45 7 1 Ignition Timing 45 7 2 Preseparator 45 7 3 Install new ignition module 45 7 4 Testing the Ignition Module 47 7 5 Spark Plug Boot Ignition Lead 48 7 6 Flywheel 48...

Page 3: ...3 Pump Diaphragm 87 12 6 4 Levers on Throttle Shaft 88 12 6 5 Adjusting Screws 89 12 7 Adjusting the Carburetor 90 12 7 1 Basic Setting 90 12 7 2 Standard setting 92 12 8 Carburetor Carrier 92 12 9 I...

Page 4: ...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 grea...

Page 5: ...e caution while carrying out maintenance and repair work on the ignition system The high voltages which occur can cause serious or fatal accidents Always wear suitable protective gloves for operations...

Page 6: ...s Centrifugal clutch without linings Clutch engages at 3 600 rpm 3 600 rpm Crankcase leakage test at gauge pressure 0 5 bar under vacuum 0 5 bar 2 2 Fuel System Carburetor leakage test at gauge pressu...

Page 7: ...ollar screw engine housing 16 0 B Collar screw M 8 D 9 Collar stud for bar engine housing repair solution 16 0 Screw P 4x12 Cover chain brake engine housing 1 5 Screw M 4x9 6 Spark arresting screen mu...

Page 8: ...chain adjuster 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 scr...

Page 9: ...tes at idle speed Engine idle speed too high Readjust idle speed screw LA Clutch springs stretched Replace the clutch springs or install new clutch Clutch springs broken Replace the clutch springs Lou...

Page 10: ...clutch Clutch drum badly worn Install new clutch drum Brake band blocked Check freedom of movement and operation of brake band Saw chain rotates at idle speed Engine idle speed too high Readjust idle...

Page 11: ...ake cable Brake cable disconnected or broken Reconnect or replace brake cable QuickStop Super Coasting brake does not disengage properly even though lockout lever is depressed Too much free travel on...

Page 12: ...dy clogged or intake hose ruptured Fit new intake hose and pickup body Valve in oil tank blocked Clean or replace valve Teeth on worm worn Install new worm Oil pump damaged or worn Install new oil pum...

Page 13: ...educe tension Starter rope can be pulled out almost without resistance crankshaft does not turn Guide peg on pawl or pawl itself is worn Fit new pawl Spring clip on pawl fatigued Fit new spring clip S...

Page 14: ...y low outside temperatures Lubricating oil on rewind spring becomes viscous spring windings stick together or moisture has got onto the rewind spring spring windings frozen together Coat rewind spring...

Page 15: ...orrect air gap between ignition module and flywheel Set air gap correctly Flywheel cracked or has other damage or pole shoes have turned blue Install new flywheel Ignition timing wrong flywheel out of...

Page 16: ...the inlet control lever Fit a new metering diaphragm Metered diaphragm deformed Fit a new metering diaphragm Poor acceleration Setting of low speed screw too lean Check basic carburetor setting correc...

Page 17: ...e carburetor Low speed screw 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 Tank...

Page 18: ...ecessary Leak on fuel hose from tank to carburetor Seal connections or install new fuel hose Setting of high speed screw H too rich Check basic carburetor setting correct if necessary Main jet bores o...

Page 19: ...g if necessary Engine does not deliver full power or runs erratically Piston rings worn or broken Fit new piston rings Muffler spark arresting screen carbonized Clean the muffler inlet and exhaust rep...

Page 20: ...b 6 4 80 100 5902RA018 TG 1 Pull boot 1 off the spark plug Unscrew the spark plug Push the locking strip 1 0000 893 5903 into the spark plug hole wide end first so that OBEN TOP faces up The locking s...

Page 21: ...brupt stop Machines with QuickStop Super The clutch drum must rotate freely when the lockout lever is depressed With the coasting brake disengaged open the throttle wide and let go of the lockout leve...

Page 22: ...e the chain brake Push the brake band 1 over the guide lugs arrows and into its seat Push the brake band 1 into its seat arrow as far as stop Fit the screw 2 on the underside of the machine and tighte...

Page 23: ...Pull the hand guard 1 and brake lever 2 off the pivot pins arrows together Remove the hand guard and brake lever Remove the spacer washer 1 and strap 2 Take the brake lever 2 out of the hand guard 1 I...

Page 24: ...ver the pivot pins arrows Turn the cam lever 1 to one side until the cam of the hand guard arrow slips passed it Push the hand guard bearing boss and the brake lever on to the pivot pins Fit the retai...

Page 25: ...w off 2710RA030 TG 1 2 off off o ff 2710RA031 TG 1 Remove the brake spring from the brake lever Remove the shroud b 6 4 Remove the fan housing b 8 2 Disconnect the spring 1 from the anchor pin arrow R...

Page 26: ...nd guard 1 and line up the holes Fit the brake cable 1 in the hole arrow Push the hand guard 1 with brake lever 2 over the machine until they are positioned against the pivot pins arrows 5902RA049 TG...

Page 27: ...sequence 5 4 1 Adjusting the brake cable If problems occur on the coasting brake even though the brake band is in order the reason may be the adjustment of the brake cable Troubleshooting b 3 2 Check...

Page 28: ...nd hold it in that position The brake band 1 must locate snugly against engine housing arrows and the clutch drum must rotate freely Install the throttle rod b 10 3 4 Fit the handle molding b 10 3 Rea...

Page 29: ...stop Fit the clamp screw 2 and tighten it down firmly Thread the brake cable 1 between the fuel hose 2 and fuel return hose 3 5902RA065 TG 1 2 5902RA260 TG 1 2 2710RA049 TG 2 4 3 1 Push the brake cab...

Page 30: ...cam lever and remove it Remove the retaining ring 3 Pull off the cam lever Check the cam lever spring and condition of cam guide n the hand guard and replace if necessary Inspect all pivot pins and re...

Page 31: ...g Before installing the new pin coat its knurled shank with threadlocking adhesive b 14 Position the new pin in the bore arrow so that the knurling on the pin meshes with the existing knurling in the...

Page 32: ...ew 3 Pull out the spur gear 2 and tensioner slide 1 Inspect the thrust pad 3 support 4 tensioner slide 1 spur gear set 2 and replace as necessary Clean all disassembled parts b 14 Lubricate thread wit...

Page 33: ...nd unscrew the stud 2 counterclockwise Coat the collar stud with threadlocking adhesive fit and tighten down firmly b 14 Reassemble all other parts in the reverse sequence 2710RA065 TG 2 1 Repair solu...

Page 34: ...ing screen see instruction manual Installing Position the machine upright Cover the exhaust port Remove any dirt from around the cylinder and exhaust port Check and clean the sealing faces arrows remo...

Page 35: ...d b 6 4 Pull off the boot and unscrew the spark plug Set the piston to top dead center This can be checked through the spark plug hole 2710RA075 TG 1 Fit the spark plug 1 and tighten it down firmly Re...

Page 36: ...n the engine the oil seals must be replaced b 6 3 After finishing the test push the ring to the right to vent the pump Continue with pressure test b 6 2 3 6 2 3 Pressure Test Carry out the same prepar...

Page 37: ...oil seal in its seat by tapping it with a suitable tube or a punch Apply puller 1 5910 890 4400 with No 3 1 jaws 0000 893 3706 Clamp the puller arms Pull out the oil seal Installing Clean the sealing...

Page 38: ...Lubricate sealing lips of new oil seal with grease b 14 Fit the installing sleeve 1 1141 893 4600 Slip the oil seal sealing lip facing the engine housing over the installing sleeve Remove the install...

Page 39: ...2 1 Remove the fan housing b 8 2 Remove the flywheel b 7 6 Remove the clutch b 4 Remove the oil pump b 11 3 Remove the filter base b 12 3 Remove the carburetor b 12 5 Remove the carburetor carrier b...

Page 40: ...the cylinder always seal it with fresh sealant on the engine pan Check the crankshaft and ball bearings and replace if necessary b 6 6 Inspect the piston and piston rings and replace if necessary b 6...

Page 41: ...he sealing face b 14 Do not coat oil seals with sealant Lubricate the piston piston rings and cylinder wall with oil b 14 Install the piston rings so that the radii at the ring gaps meet at the fixing...

Page 42: ...ng 1 off the straight crankshaft stub clutch side The crankshaft connecting rod and needle bearing form an inseparable unit When fitting a replacement crankshaft always install new ball bearings and o...

Page 43: ...the end of the drift lightly with a hammer Hold the piston steady during this process to ensure that no jolts are transmitted to the connecting rod Remove the piston Inspect the piston rings and repla...

Page 44: ...base Remove the sleeve and slip it onto the other end of the shank the inner pin must point towards the flat face Fit the snap ring 1 so that its gap arrow is on the piston s vertical axis it must poi...

Page 45: ...so that the radii face upward arrows 5902RA160 TG 5902RA161 TG Carefully fit the piston rings over the piston they might otherwise break Install the piston rings so that the radii at the ring gap meet...

Page 46: ...iring and stop switch are in good condition 2710RA130 TG 2 1 7 1 Ignition Timing Ignition timing is fixed and cannot be adjusted during repair work Since there is no mechanical wear in these systems i...

Page 47: ...net poles arrows are next to the ignition module 1 Press the ignition module 1 against the setting gauge Position the ground wire terminal so that it points towards the cable guide hold it steady when...

Page 48: ...nition system with the aid of the troubleshooting chart b 7 8 Using the ZAT 3 ignition tester 5910 850 4520 Before starting the test install a new spark plug in the cylinder and tighten it down firmly...

Page 49: ...d s insulation about 15 mm from the end of the lead Pinch the hook of the leg spring into the pierced hole in the center of the lead arrow Coat the inside of the spark plug boot with STIHL press fluid...

Page 50: ...all other parts in the reverse sequence 7 7 Short Circuit Wire The ground and short circuit wires are combined in a wiring harness If the spark plug ignition lead and spark plug boot are in order che...

Page 51: ...l the wiring harness 1 out of the guide arrow Remove the switch shaft b 10 1 Pull the short circuit wire 1 out from behind the tab arrow Pull the ring terminal 1 off the peg arrow Remove the switch sh...

Page 52: ...he cable lug 1 so that it points towards the cable guide hold it steady when tightening and make sure it does not twist Short circuit wire Crimped side of terminal 3 must face the engine housing Conne...

Page 53: ...and install the ground wire as described for the short circuit wire Check for contact and continuity and replace the wiring harness if necessary b 7 7 7 7 4 Contact Spring Remove the shroud b 6 4 Rem...

Page 54: ...TG 2 1 2710RA163 TG 1 The tab arrow on the contact spring 1 must locate securely on the edge of the filter base Install the filter base b 12 3 The short circuit wire 1 must be above the ground wire s...

Page 55: ...d Electrode gap correct Contacts shorted Clean readjust or replace the plug b 7 4 Check the spark plug boot Firmly seated on plug leg spring Leg spring hook in center of ignition lead Boot damaged If...

Page 56: ...ere chafing Spark plug boot Holes cracks Resistance spark plug boot to ground spec 1 5 12 k Check resistance of ignition lead spark plug boot and ignition module removed Spec 10 If necessary install n...

Page 57: ...ystem or carburetor Check engine for leaks Check position of flywheel on crankshaft b 6 2 b 7 6 yes Check operation of stop switch Short circuit wire chafed Function between contact spring and switch...

Page 58: ...HL special lubricant b 14 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 rewind spring C...

Page 59: ...tarter rope the rotor turns and the peg on the pawl moves in the direction of the spring loop the pawl moves outwards Reassemble all other parts in the reverse sequence 2710RA219 TG 1 2710RA220 TG Mod...

Page 60: ...n arrows Fit the pawls 1 on the pins 2 on the flywheel preload the torsion springs at the same time and locate them against the ribs arrow Fit the pawls 1 so that they can move towards the center of t...

Page 61: ...pring may pop out and unwind Check the rope rotor and replace if necessary Coat bore in rope rotor with STIHL special lubricant b 14 Installing Fit the rope rotor on the starter post so that the inner...

Page 62: ...Models with ErgoStart Thread the new rope through the side arrow of the starter grip Pull the rope into the starter grip until the knot is properly seated in the grip small arrow 4903RA132 TG 2710RA22...

Page 63: ...extended it must still be possible to rotate the rope rotor at least another full turn before maximum spring tension is reached If this is not the case reduce spring tension since there is otherwise a...

Page 64: ...902RA225 TG Press the frame 1 against the rewind spring and rotate it slightly clockwise until the spring is properly seated The rewind spring may pop out and unwind Carefully remove the frame and kee...

Page 65: ...wind spring 5902RA221 TG 1 5902RA222 TG 1 Models with ErgoStart As the spring seat is deeper on this model the rewind spring cannot be fitted directly in the fan housing Fit the anchor loop in its sea...

Page 66: ...ffer 2 onto the peg 1 on the handlebar as far as stop The peg s head arrow must locate properly on the buffer Unscrew the AV spring 1 Unscrew the bearing plug 2 Check the AV spring and plug replace if...

Page 67: ...pring is located between the handle frame and cylinder Remove the shroud b 6 4 Remove the air filter b 12 1 Push the air guide shroud 1 in direction of rear handle Take out the screw 2 Remove the hand...

Page 68: ...engine housing Use STIHL press fluid to simplify assembly b 14 Push the stop buffer 1 into the bore arrow as far as stop the peg 2 must engage the stop buffer 1 9 4 1 Stop Buffer at Ignition Side Rem...

Page 69: ...he bores Use STIHL press fluid to simplify assembly b 14 Push the tapered ends of the buffers 1 fully into the bores arrows The tapered ends arrows must be properly seated on the other sides of the bo...

Page 70: ...ebar 1 check it and replace if necessary Check the annular buffer and replace it if necessary b 9 1 Installing Push the handlebar buffer 1 first into the engine housing Push the AV spring 1 into its s...

Page 71: ...lace if necessary 2710RA192 TG 1 2 5902RA584 TG 1 2 Installing Place the switch lever 2 in position Fit the short circuit wire 1 on the switch lever b 7 7 2 When installing the switch lever lift the c...

Page 72: ...Inspect the lockout lever throttle trigger and torsion spring replace as necessary Installing Attach the torsion spring 1 to the trigger 2 note the installed position arrow 2710RA331 TG 1 4 3 2 5902R...

Page 73: ...parts in the reverse sequence 10 3 Throttle Trigger Lockout Lever QuickStop Super Lubricate sliding and bearing points with grease after disassembly To remove the handle molding press the tabs 1 on t...

Page 74: ...it is recessed by same amount at both sides Attach the throttle rod 1 to the trigger 2 and fit it in the guide arrow Engage tabs 2 of handle molding 1 in the openings arrow Press the lockout lever dow...

Page 75: ...bly Remove the handle molding b 10 3 Use a drift 1 to drive out the pin arrow Take out the lockout lever Push out the bushing 1 Remove the torsion spring Inspect the lockout lever throttle trigger and...

Page 76: ...old start until the choke rod 1 snaps into position Check operation Check that the choke rod is properly seated Reassemble all other parts in the reverse sequence 10 3 4 Throttle Rod Remove the thrott...

Page 77: ...throttle rod 1 between the tank housing and air guide shroud and rotate it about 90 at the same time Pass the throttle rod 1 through the opening arrow Turn the bent end 1 clockwise and push it under t...

Page 78: ...on Hose Open the oil tank cap and drain the oil tank b 1 Remove the clutch b 4 Remove the brake band b 5 2 Remove the oil pump b 11 3 Remove the oil suction hose 1 together with the pickup body Check...

Page 79: ...ling Replace the sealing ring 1 always use a new sealing ring Position the oil suction hose 1 so that the lugs arrows are in alignment Push the oil suction hose 1 onto the nipple 2710RA250 TG 1 1 2710...

Page 80: ...to carefully drive the valve out of its seat in the housing and into the oil tank Remove the old valve 1 from the oil tank 2710RA254 TG 219RA476 TG 1 Installing Check correct installed position Insert...

Page 81: ...Remove the air filter b 12 1 Unscrew the nuts arrows Remove the baffle 1 Check the baffle and replace it if necessary Reassemble in the reverse sequence 12 3 Filter Base Remove the air filter b 12 1...

Page 82: ...buffer arrow at ignition side 2710RA260 TG 1 1 2710RA261 TG 1 2 3 2710RA207 TG 1 Push the short short circuit 1 through the opening arrow Position the short circuit wire 1 so that it is above the gro...

Page 83: ...to the guide until it snaps into place Push the lugs 2 of the air guide shroud 1 into their seats arrows Place the air guide shroud 1 in position Insert and tighten down the screw 2 firmly 5902RA465 T...

Page 84: ...utter 1 into the guide until it snaps into place Push the retainer 1 with fuel pump into the guide as far as stop Position the hose clip 2 so that its locking tabs face the air guide shroud and press...

Page 85: ...the fuel hose only when the tank cap is open 2710RA269 TG 1 2 Push the fuel hose 1 back a little the fuel hose is disconnected Models with manual fuel pump Remove the fuel hose 1 All models Remove the...

Page 86: ...nipple onto the carburetor s fuel stub arrow Push the pressure hose of pump 0000 850 1300 onto the nipple 2710RA333 TG 1 2 2 1 5902RA380 TG Push the ring 1 to the right and pump air into the carburet...

Page 87: ...2 and gasket 1 Position the gasket 1 and metering diaphragm 2 so that the holes arrows are in line with the recess 3 Position the end cover 1 so that the stub 3 points in the direction of the choke sh...

Page 88: ...shooting b 3 6 Remove the carburetor b 12 5 Take out the screw 2 Remove the end cover 1 If the gasket and pump diaphragm are stuck to the carburetor remove them very carefully 5902RA391 TG 2 1 Careful...

Page 89: ...in the carburetor body Check that the pump diaphragm and gasket are properly seated Insert and tighten down the screw 2 firmly Reassemble all other parts in the reverse sequence 12 6 4 Levers on Thro...

Page 90: ...ed screw L as far as stop Continue with the high speed screw H High speed screw The high speed screw H has a limiter cap which has to be removed before the screw is removed Screw the puller 1 5910 890...

Page 91: ...ic setting is necessary only if the high speed screw H or low speed screw L has to be replaced or after cleaning and adjusting the carburetor from scratch It is necessary to carry out the basic settin...

Page 92: ...high speed screw H to set the engine s maximum speed to 13 000 rpm starting with H 1 1 2 turns open Do not attempt to make the mixture any leaner after obtaining an engine speed of 13 000 rpm the igni...

Page 93: ...hen turn it back 1 full turn Saw chain runs while engine is idling Turn the idle speed screw LA counterclockwise until the chain stops running then turn it back one full turn Erratic idling behavior p...

Page 94: ...lace if necessary b 12 9 Installing To fit the manifold 2 through the carburetor carrier s opening wind a piece of string 1 about 15 cm long around the back of manifold flange Place the carburetor car...

Page 95: ...he shroud b 6 4 Remove the carburetor b 12 5 Remove the carburetor carrier b 12 8 Remove the air guide shroud b 12 4 Models with manual fuel pump b 12 4 1 Take out the screws 1 Remove the intake manif...

Page 96: ...tank Equalization of pressure takes place via the tank vent There must be no buildup of vacuum in the tank Clean the area around the tank vent If necessary install a new tank vent or tank b 12 10 or...

Page 97: ...pply system always check the fuel tank and the pickup body first 2710RA299 TG 1 Troubleshooting b 3 6 or b 3 7 Clean the fuel tank if necessary Open the tank cap and drain the tank Pour a small amount...

Page 98: ...nnector Pull the connector 1 off the fuel hose 2 Remove the pickup body b 12 11 1 Pull the fuel suction hose 1 out of the fuel tank Replace the fuel hose and fuel return hose Check the connector and r...

Page 99: ...uel hose 2 connector first under the brake cable Push the connector 1 into the fuel suction hose Line up the fuel hose 2 and connector with the channel arrows Position the fuel hose 1 so that it is on...

Page 100: ...suction hose 1 from the fuel tank Do not overstretch the fuel suction hose Fit the pickup body b 12 11 1 Close the tank cap Reassemble all other parts in the reverse sequence 12 11 3 Fuel Hose Models...

Page 101: ...t 1 Replace the fuel return hose Check the connector and grommet and replace if necessary Remove the fuel suction hose 1 b 12 11 2 5902RA491 TG 2 1 1 2710RA305 TG 1 2710RA306 TG Installing Install the...

Page 102: ...ng ribs arrows and push it into the grommet 3 Install the fuel hose 1 b 12 11 2 Tie a thin piece of string 1 about 25 cm long around the flange arrow of the fuel return hose 2710RA311 TG 2 1 3 2710RA3...

Page 103: ...it is next to the short circuit wire s grommet 1 Push the fuel return hose 2 into the guides arrows Install the carburetor b 12 5 Push the fuel suction hose 1 onto the nipples arrows as far as stop Ch...

Page 104: ...ration fuel must flow when the fuel pump is operated Reassemble all other parts in the reverse sequence 12 11 5 Tank Housing Drain the fuel tank b 1 Remove the handlebar b 9 5 Remove the carburetor b...

Page 105: ...rough the opening arrow into the engine housing Models with manual fuel pump Tie a thin piece of string 1 about 25 cm long around the flange arrow of the fuel return hose Coat the flange of the fuel r...

Page 106: ...de the bore arrow Install the handlebar b 9 5 Lift the tank housing 2 Insert and tighten down the screw 1 firmly 2710RA319 TG 1 2710RA321 TG 2 1 2 2710RA184 TG 1 Push the connector 1 with fuel return...

Page 107: ...tting gauge 1111 890 6400 Adjusting air gap between the ignition module and flywheel 8 Installing tool 1116 893 4800 Installing rewind spring 9 Assembly tube 1117 890 0900 Attaching springs 10 Test fl...

Page 108: ...hing springs on clutch shoes 22 Assembly stand 5910 890 3101 Holding saw for repairs 23 Puller 5910 890 4400 Removing oil seals 24 Puller 5910 890 4502 Pull off the limiter cap 25 Puller 5910 890 4504...

Page 109: ...wind spring in fan housing 4 STIHL press fluid OH 723 0781 957 9000 Rubber components AV buffers 5 Dirko HT red sealant 0783 830 2000 Sealing engine pan cylinder 6 Medium strength threadlocking adhesi...

Page 110: ...englisch english 0455 574 0123 M1 15 B11 FST Printed in Germany...