Stihl MS 661 Manual Download Page 106

Page: 106 / 138

105

MS 661, MS 661 C-M

Fit the pump diaphragm (1) on
the gasket so that their tabs
(arrow) are in alignment and its
holes engage the pegs (2).

Gasket and pump diaphragm are
now held in position.

Fit the end cover (1) from below
so that the pump diaphragm and
gasket remain in position.

Align the end cover (1) so that the
stub (2) faces the throttle shutter.

1166RA256 TG

1166RA257 TG

Move the end cover (1) back and
forth until its pegs engage the
holes in the carburetor body.

– Check that the pump diaphragm

and gasket are properly seated.

Insert and tighten down the
screws (2) firmly.

Versions with carburetor heating

Push the wire (1) into the guides
(arrows).

1166RA258 TG

1166RA260 TG

Move the end cover (1) back and
forth until its pegs engage the
holes in the carburetor body.

Fit the thermostatic switch (2) so
that it engages the recesses
(arrows).

– Check that the pump diaphragm

and gasket are properly seated.

Insert and tighten down the
screws (3) firmly.

All models

– Reassemble all other parts in the

reverse sequence.

13.5.6 Lever on Throttle Shaft

– Remove the carburetor,

13.4

– Carburetor troubleshooting,

3.6

1166RA259 TG

3
1

Summary of Contents for MS 661

Page 1: ...STIH STIHL MS 661 661 C M 2013 07 ...

Page 2: ...7 5 Spark Test 42 7 6 Spark Plug Boot Ignition Lead 43 7 7 Flywheel 44 7 8 Testing Wiring Harness 45 7 8 1 Testing Wiring Harness without M Tronic 45 7 8 2 Testing Wiring Harness with M Tronic 46 7 8 3 Testing Ground Wire 46 7 9 Short Circuit Wire without M Tronic Removing and Installing 46 7 10 Short Circuit Wire with M Tronic Removing and Installing 48 7 11 Short Circuit Wire with M Tronic and H...

Page 3: ...M Tronic 106 13 6 Adjusting the Carburetor Models with M Tronic 107 13 7 Adjusting the Carburetor Models without M Tronic 107 13 7 1 Adjusting Screws 107 13 8 Adjusting the Carburetor 109 13 8 1 Basic Setting 109 13 8 2 Setting 109 13 8 3 Standard Setting 110 13 9 Manifold 111 13 9 1 Impulse Hose 112 13 10 Tank Vent 113 13 10 1 Testing 113 13 10 2 Removing and Installing 113 13 11 Fuel Intake 114 ...

Page 4: ...he descriptions Action to be taken that is shown in the illustration above the text Action to be taken that is not shown in the illustration above the text In the illustrations A Pointer short arrow aDirection of movement b 4 2 Reference to another chapter i e chapter 4 2 in this example Service manuals and all technical information bulletins are intended exclusively for the use of properly equipp...

Page 5: ...matically after the engine stops The engine can start at any time if the rewind starter is operated Always wear suitable protective gloves for operations in which components are heated for assembly or disassembly Improper handling may result in burns or other serious injuries Always replace damaged parts Check disassembled parts for wear or damage before re installing replace as necessary Run the ...

Page 6: ...vent at gauge pressure 0 5 bar Fuel see instruction manual 2 3 Ignition System Air gap between ignition module and fanwheel 0 30 0 05 0 10 mm Spark plug resistor type NGK BPMR 7 A BOSCH WSR 6 F Electrode gap 0 5 mm 2 4 Chain Lubrication Speed controlled oil pump with reciprocating piston and manual flow control Standard Uprated Standard Uprated with pin driven home Settings for oil delivery rate m...

Page 7: ...ews with medium strength Loctite 242 or 243 and screws previously coated with threadlocking adhesive with Loctite see list of screws below Power screwdriver setting for polymer P and DG screws max 500 rpm Do not use an impact wrench for releasing or tightening screws Do not mix up screws with and without binding heads Fastener Thread size For component Torque Nm Remarks Screw M 4x8 Chain tensioner...

Page 8: ... Muffler crankcase 10 0 4 5 6 Screw M 5x30 Muffler cylinder 10 0 3 4 6 Screw M 5x6 Muffler casing top 6 0 4 5 Screw M 4x12 Switch unit carburetor 2 0 5 Screw P 4x10 Guard handle housing 1 5 Nut M 10x1 Flywheel crankshaft 45 0 7 Screw M 4x8 Side plate crankcase 2 0 4 Screw M 3x20 Manifold clamp cylinder 0 5 Screw M 4x20 Ignition module control unit crankcase 4 0 5 Stud M 5 Stud cylinder 8 0 5 Screw...

Page 9: ...ng Engine idle speed too high Depending on model Readjust idle speed screw LA or check M Tronic Clutch springs stretched Replace the clutch springs or install new clutch Clutch springs broken Replace the clutch springs Loud noises Clutch springs stretched Replace all clutch springs Needle cage damaged Fit new needle cage Clutch shoe retainer broken Install new retainer or clutch Clutch shoes and c...

Page 10: ...t chain of correct pitch Insufficient chain lubrication Check chain lubrication Saw chain stops under full load Brake band blocked Check freedom of movement and operation of brake band Saw chain does not stop immediately when brake is activated Chain brake spring stretched broken Fit new brake spring Brake band stretched worn broken Fit new brake band Clutch drum worn Install new clutch drum ...

Page 11: ...ace valve Teeth on worm worn Install new worm Oil pump damaged or worn Install new oil pump Machine losing chain oil Oil pump damaged or worn Install new oil pump Oil suction hose connection damaged Install new oil suction hose Gasket between two halves of crankcase faulty or crankcase cracked Install new gasket inspect both halves of crankcase and replace if necessary Oil pump delivers insufficie...

Page 12: ... pulled out almost without resistance crankshaft does not turn Guide pegs on pawls or pawls themselves are worn Replace pawls Spring clip on pawl fatigued Fit new spring clip Spring clip not installed properly Install spring clip correctly Starter rope is difficult to pull or rewinds very slowly Starter mechanism is very dirty Thoroughly clean complete starter mechanism At very low outside tempera...

Page 13: ...ct mixture of fuel and oil Incorrect air gap between ignition module control unit and flywheel Set air gap correctly Flywheel cracked or damaged or pole shoes have turned blue Install new flywheel Ignition timing wrong flywheel out of adjustment key has sheared off or slot in flywheel is worn Install new flywheel or key Weak magnetization in flywheel Install new flywheel Irregular spark Check oper...

Page 14: ...rmed and presses constantly against the inlet control lever Fit new metering diaphragm Metered diaphragm deformed Fit new metering diaphragm Poor acceleration Low speed screw L and or high speed screw H too lean Check basic carburetor setting correct if necessary Models with M Tronic carburetor setting too lean Check M Tronic with STIHL MDG 1 and troubleshooting chart b 8 7 adjust or calibrate con...

Page 15: ...ol unit b 8 1 setting of idle speed screw must not be changed Tank vent faulty Fit new tank vent Leak in fuel hose between pickup body and carburetor Seal connections or install new fuel hose Engine will not idle idle speed too high Setting of idle speed screw LA incorrect throttle shutter opened too wide Readjust idle speed screw LA counterclockwise Models with M Tronic idle speed too high Check ...

Page 16: ...ty Fit new tank vent Fuel pickup body dirty Fit new pickup body Fuel strainer dirty Clean fuel strainer in carburetor replace if necessary Leak in fuel hose between pickup body and carburetor Seal connections or install new fuel hose Setting of high speed screw H too rich Check basic carburetor setting correct if necessary Models with M Tronic carburetor setting too rich Check M Tronic with STIHL ...

Page 17: ...ower and a very low maximum speed Choke shutter does not open fully Check carburetor and choke shaft service or replace if necessary Models with M Tronic carburetor setting too rich Check M Tronic with STIHL MDG 1 and troubleshooting chart b 8 7 adjust or calibrate control unit b 8 1 ...

Page 18: ...t deliver full power or runs erratically Piston rings worn or broken Install new piston rings Muffler spark arresting screen carbonized Clean the muffler inlet and exhaust replace spark arresting screen replace muffler if necessary Air filter dirty Clean or replace air filter Fuel hose kinked or torn Fit new hose or position it free from kinks Decompression valve is not closed Close and check deco...

Page 19: ...nst the cylinder wall arrow as shown in the illustration Apply wrench to hexagon arrow and unscrew the clutch 1 Note that the clutch has a left hand thread Disassembling Use hook 2 5910 890 2800 to remove the clutch springs 1 1166RA002 TG 1 1 1166RA003 TG o f f o f f off 5902RA006 TG 2 1 If clutch is seriously worn install new set of 3 clutch shoes Assembling Fit the retainers and push the clutch ...

Page 20: ...e braking time is in order if deceleration of the saw chain is imperceptible to the eye a fraction of a second If the chain brake does not operate properly refer to troubleshooting b 3 2 5 2 Brake Band Troubleshooting b 3 2 Remove the clutch drum Remove the clutch b 4 2 Take out the screw and remove the side plate Take out the screws 1 and remove the cover 2 Engage the chain brake Brake band no lo...

Page 21: ...assembly tool 1117 890 0900 to disconnect the brake spring 1 from the anchor pin arrow and the brake lever Remove the rewind starter b 9 2 Remove the E clip 1 then pull the hand guard 2 and brake lever 3 off the pivot pins together Check the pivot pins replace if necessary b 5 5 Inspect the cam lever and replace if necessary b 5 4 1 1166RA012 TG 1166RA013 TG 2 1 3 Installing Clean pins and disasse...

Page 22: ...nect the spring 1 from the anchor pin 2 and cam lever 4 Remove the E clip 3 and pull off the cam lever 4 Check the cam lever spring and cam running face on the hand guard and replace as necessary Inspect all pivot pins and replace if necessary b 5 5 Installing Lubricate the pivot pins with STIHL grease b 16 Install the cam lever so that the lobe points in the direction of the carburetor Fit the E ...

Page 23: ... 4 3 4 7 mm Drive home the pins 3 4 and 5 as specified below 1 2 1166RA022 TG a b 1166RA023 TG 1 2 1166RA024 TG 4 3 5 Pin 3 a about 9 9 10 1 mm Pin 4 b about 4 6 4 8 mm Pin 5 c about 5 1 5 3 mm Lubricate the brake lever and cam lever with STIHL grease b 16 Reassemble all other parts in the reverse sequence 5 6 Chain Tensioner Troubleshooting b 3 2 Remove the side plate b 5 2 Rotate the spur gear 1...

Page 24: ... to replace the nuts Remove the chain sprocket cover Screw the short stud marked S of special tool 1 5910 893 9601 into the collar nut 2 as far as stop Turn the sprocket cover over and clamp the special tool s hexagon in a vise Use an 11mm drill to drill away the flange of the captive nuts the shoulder in the sprocket cover must not be drilled out 1166RA028 TG 1 2 2 1166RA029 TG Remove the collar ...

Page 25: ...stall a new gasket Remove and install the spark arresting screen see instruction manual Installing Clean away any dirt from the cylinder and exhaust port Check and clean the sealing faces arrows on exhaust port heat shield and muffler remove any gasket residue make sure there is no gasket residue or dirt particles in the exhaust port Always replace components with damaged sealing faces 1166RA034 T...

Page 26: ... 2 1 Preparations Remove the filter cover Remove the shroud b 6 4 The spark plug 1 must be tightened down firmly Remove the decompression valve b 6 9 Fit the plug 2 1122 025 2200 and tighten it down firmly Remove the exhaust casing and loosen the muffler screws b 6 1 Fit the sealing plate 1 0000 855 8106 on the exhaust port between the gasket heat shield and cylinder Tighten the screws moderately ...

Page 27: ...the pressure gauge 3 indicates a pressure of 0 5 bar If this pressure remains constant for at least 20 seconds the crankcase is airtight If the pressure drops the leak must be located and the faulty part replaced To find the leak coat the suspect area with oil and pressurize the crankcase again Bubbles will appear if a leak exists After finishing the test push the ring to the left to vent the pump...

Page 28: ...6 Reassemble all other parts in the reverse sequence 6 3 2 Clutch Side Remove the clutch b 4 2 Remove the retaining ring 1 Remove the oil pump b 12 3 Take care not to damage the crankshaft stub Free off the oil seal in its seat by tapping it with a suitable tube or a punch 1 1166RA048 TG 1166RA049 TG 1 Apply puller 1 5910 890 4400 with No 3 1 jaws 0000 893 3706 clamp the puller arms and pull out t...

Page 29: ... whether or not the crankshaft has to be removed as well Cylinder installed To remove the flywheel and clutch the crankshaft has to be blocked by inserting the locking strip in the spark plug hole b 4 2 Cylinder removed To remove the flywheel and clutch the crankshaft has to be blocked by resting the piston on the piston support special tool Remove the shroud b 6 4 Remove the rewind starter b 9 2 ...

Page 30: ...with damaged sealing faces Always use a new cylinder gasket when re installing the cylinder Installing Coat the inside of the manifold with STIHL press fluid b 16 Insert new washer 1 through larger diameter of manifold 2 as shown Position the washer 1 so that it is properly seated arrows 1166RA452 TG 1 1 2 Coat the inside of the manifold flange with STIHL press fluid b 16 Washer must be installed ...

Page 31: ...ifold 2 points towards the tank housing While sliding the cylinder over the piston hold the clamping strap tightly around the piston so that the rings do not project they might otherwise break Slide the cylinder over the piston the clamping strap moves downwards at the same time 1166RA063 TG 1 1 1166RA064 TG 2 Remove the clamping strap and piston support Wind a piece of string 1 around the manifol...

Page 32: ...ar b 10 5 Version with heating b 10 5 1 Remove the flywheel b 7 7 Machines with handle heating Remove the generator b 14 7 Remove wiring harness at ignition side b 7 9 models with M Tronic heating b 7 10 Remove the cylinder b 6 5 Remove the piston b 6 7 Remove the tank housing b 13 11 4 Always install new bearings and oil seals after removing the crankshaft b 6 6 1 and b 6 3 Clutch side of crankca...

Page 33: ...nscrew the spindle 1 until the drilled plate 2 butts against the crankcase left hand thread Fit the plate 2 5910 893 2101 against the ignition side of the crankcase so that the number 31 arrow is at the bottom 43 9 7 9 7 9 31 2 27 6 31 31 3 1 1166RA075 TG 1166RA076 TG 1 3 3 2 3 4 31 Insert two M5x72 screws 3 in the holes marked 31 and tighten them down until they butt against the crankcase Fit thr...

Page 34: ...ub of crankshaft with oil Position the tapered stub of the crankshaft above the ball bearing at the ignition side and push it home Position the screw sleeve 2 5910 893 2421 on the crankshaft thread 1 and screw it into place 3443RA111 TG 1 1 2 1166RA069 TG Turn the spindle 1 to position the drilled plate 5910 893 2101 against the ignition side of the crankcase and line it up so that the number 31 i...

Page 35: ...910 007 2222 to install the crankcase Do not remove the oil pump for this purpose Coat the straight stub of the crankshaft with oil Position the clutch side of the crankcase on the straight crankshaft stub and the two screws Screw the spindle fully into the service tool Screw the threaded sleeve 1 5910 893 2202 onto the spindle as far as stop left hand thread 165RA133 TG 1 Apply the screw sleeve t...

Page 36: ...t not be damaged in any way New crankcase halves are supplied with the main parts preassembled see the parts list Parts not supplied with the new crankcase must be transferred from the original crankcase check the parts and replace if necessary If a new crankcase is installed the machine s serial number must be stamped on it with 2 5 mm figure stamps If the original crankcase is used again replace...

Page 37: ... has no stop in its bearing seat the mounted oil pump is used as a stop Heat area of bearing seat to about 160 C 320 F Position the ball bearing so that the oil seal s seat faces the oil pump and then press home the ball bearing until it butts against the oil pump This operation must be carried out quickly because the bearing absorbs heat and begins to expand Check that ball bearing is properly se...

Page 38: ... 1 can be pushed through the installed snap ring Place the piston on the connecting rod Slide the assembly drift 1 1108 893 4700 small diameter first through the piston and small end needle cage and line up the piston Lubricate the piston pin 2 with oil Fit the piston pin 2 on the assembly drift 1 and slide it into the piston Prepare snap ring for installation with installing tool 5910 890 2212 11...

Page 39: ... grooves they might otherwise break Install the piston b 6 7 Reassemble all other parts in the reverse sequence 1166RA095 TG 1166RA096 TG 6 9 Decompression Valve Remove the shroud b 6 4 Unscrew the decompression valve 1 Check the sealing cone arrow on the decompression valve for damage If the sealing cone does not close completely or shows signs of damage install a new decompression valve Fit the ...

Page 40: ... Unit Ignition module The ignition module accommodates all the components required to control ignition timing There are two electrical connections on the coil body the high voltage output 1 for the ignition lead the connector tag 2 for the short circuit wire Testing in the workshop is limited to a spark test A new ignition module must be installed if no ignition spark is obtained after checking th...

Page 41: ...nition lead if necessary b 7 6 Fit the ignition module control unit 1 and insert the screws 2 do not tighten down yet Push the ignition module control unit back and slide the setting gauge 1 1111 890 6400 between the arms of the ignition module and the flywheel magnet 1166RA103 TG 2 2 1 1166RA104 TG 1 The setting gauge is not shown in the illustration Push the ignition module control unit 1 back a...

Page 42: ... engine may start and accelerate during the test To test the ignition module use either the ZAT 4 ignition system tester 5910 850 4503 or the ZAT 3 ignition system tester 5910 850 4520 If a spark is visible the ignition system is in order If no spark is visible in the window check the ignition system with the aid of the troubleshooting chart b 7 13 The test refers only to a spark test not to ignit...

Page 43: ... system 5910 850 4503 Before starting the test install a new spark plug in the cylinder and tighten it down firmly Connect spark plug boot to the input terminal 1 Push the tester s output terminal 3 on to the spark plug High voltage risk of electric shock Crank the engine quickly with the rewind starter and check spark in the tester s window 2 The engine may start and accelerate during the test If...

Page 44: ...ull the grommet 1 off the high voltage output arrow Unscrew the ignition lead 2 from the ignition module control unit and pull the grommet 1 off the ignition lead Remove the cover 3 from the spark plug boot Use suitable pliers to pull the leg spring out of the spark plug boot and unhook it from the ignition lead Pull the spark plug boot and cable retainer off the ignition lead 1166RA111 TG 1 3 2 6...

Page 45: ...tion lead into the ignition module control unit Push the grommet 1 into position Install the ignition module control unit and set the air gap b 7 3 Reassemble all other parts in the reverse sequence 7 7 Flywheel Remove the shroud b 6 4 Remove the rewind starter b 9 2 Use locking strip to block the piston b 4 2 Unscrew the flywheel nut 1 1166RA113 TG 1 1166RA114 TG 1 Screw puller 1 1106 890 4501 in...

Page 46: ...hort circuit wires are combined in a wiring harness If the spark plug ignition lead and spark plug boot are in order check the short circuit wire Remove the rewind starter b 9 2 1166RA118 TG Pull the short circuit wire 1 out of the guide arrow and disconnect the terminal 2 Connect the ohmmeter to ground 3 and the short circuit wire 1 Set the Master Control lever to 0 The resistance measured must b...

Page 47: ...place wiring harness if necessary 1166RA120 TG 2 1 7 9 Short Circuit Wire without M Tronic Removing and Installing Remove the shroud b 6 4 Remove the rewind starter b 9 2 Remove the ignition module b 7 3 Take out the screw 1 and pull the ground wire 2 out of the guide arrow Press out grommet 1 in direction of cylinder and pull wiring harness 2 out in direction of cylinder Remove the switch shaft b...

Page 48: ...Position the wires next to one another without crossing over Slip the grommet 1 over the wiring harness 2 so that slope arrow faces the crankcase Slide the grommet 1 into position sideways and push it home until it is properly seated in the crankcase 1166RA127 TG 2 1 1166RA128 TG 2 1 1166RA129 TG 1 Install the tank housing b 13 11 4 Install the carburetor b 13 4 Remove the contact spring and retai...

Page 49: ... wire 1 ground wire 2 and short circuit wire 3 out of the guides arrows Press lug arrow on grommet 1 in direction of cylinder and push it out sideways Remove the wiring harness with grommets Remove grommet 1 from the wiring harness via lateral opening arrow and pull off grommet 2 in direction of ring terminals Check the wiring harness and replace if necessary 1166RA135 TG 1 2 3 1 1166RA431 TG 2 1 ...

Page 50: ...w in the grommet 3 so that the black wire is at the bottom and the red and yellow wires are in the order shown Do not cross the wires Pass the wiring harness 1 ring terminals first through the opening from outside cylinder side and into the carburetor box Place the grommet 2 in position locate its groove and slide it in sideways until the lug engages at the other side 1 2 1166RA433 TG 3 1 1166RA43...

Page 51: ...cable lug 1 so that its crimped side faces outwards and then push the ground wire 2 into the guide arrow Insert and tighten down the screw 3 firmly Install the control unit b 7 2 Reassemble all other parts in the reverse sequence 1 1166RA437 TG 3 1 2 1166RA438 TG 7 11 Short Circuit Wire with M Tronic and Heating Removing and Installing Remove the shroud b 6 4 Remove the rewind starter b 9 2 Remove...

Page 52: ...ew 1 has already been removed on machines with carburetor heating Pull the ground wire 1 and short circuit wire 2 out of the guides arrows Press lug arrow on grommet 1 in direction of cylinder and push it out sideways 1166RA137 TG 1 2 3 1166RA138 TG 2 1 1166RA139 TG 1 Remove the wiring harnesses with grommets Remove grommet 1 from the wiring harness via lateral opening arrow and pull off grommet 2...

Page 53: ...w wires are in the order shown Fit the wiring harness 3 with the two wires so that it is above wiring harness 2 and the black wire is at the top Do not cross the wires Pass the wiring harnesses 1 2 ring terminals first through the opening from outside cylinder side and into the carburetor box Place the grommet 3 in position locate its groove and slide it in sideways until the lug engages at the ot...

Page 54: ...ng in the crankcase until it is properly seated Install the tank housing b 13 11 4 Install the carburetor b 13 4 Install the contact spring and retainer b 7 12 Install the switch shaft b 11 1 1 check its operation b 7 12 The grommet 1 must be properly seated in the opening Pull the wiring harnesses through until the insulating tubes 2 3 project 1166RA153 TG 1 1166RA154 TG 1 Position cable lug of g...

Page 55: ...filter base b 13 3 Remove the switch shaft b 11 1 1 All models Lift locking tabs arrows and pull out the retainer 1 part way disconnect the throttle rod 2 from the carburetor 1 at the same time 1166RA158 TG 1 2 3 Models with M Tronic Pull out retainer 1 part way and disconnect terminal 2 All models Lift the contact spring 1 a little and ease it over the tab arrow Ease the contact spring 1 out of t...

Page 56: ... position it behind the stop arrow on the retainer 3 Position the contact spring 1 against the ring terminal and guide pin arrows Lift connector tag 2 on contact spring 1 and move it over the stop 3 take care not to overstretch the contact spring Push the short circuit wire 4 through the ring 5 1166RA164 TG 1 2 3 1166RA165 TG 1 5 2 4 3 Models with M Tronic heating Push terminal 1 onto the connecto...

Page 57: ...ows allow for movement Models with M Tronic Short circuit wire 1 and ground wire 2 must be properly located in the guides 3 4 the loops arrows allow for movement 1166RA221 TG 2 3 4 1 4 6 1166RA441 TG 1 2 3 5 7 The M Tronic s black wire 5 must locate properly in the guides 6 7 loop arrow allows for movement Checking operation of all models The short circuit wire s ring terminal 1 must touch the con...

Page 58: ... Electrode gap correct Contacts shorted Clean readjust or replace the spark plug b 7 5 Check the spark plug boot Firmly seated on plug leg spring Leg spring hook in center of ignition lead Boot damaged If necessary install new spark plug boot and or leg spring b 7 6 Test ignition system with ZAT 3 or ZAT 4 use ZAT 3 as main spark gap see TI 32 94 b 7 5 1 ...

Page 59: ...hafing Spark plug boot Holes cracks Resistance spark plug boot to ground spec 1 5 12 kΩ Check resistance of ignition lead spark plug boot and control unit removed Spec spec 10 Ω If necessary install new spark plug boot and or control unit b 7 6 Check short circuit wire Wire damaged Connectors firmly seated Check continuity replace wiring harness if necessary b 7 8 1 1 3 yes no 2 Ignition spark spa...

Page 60: ...ystem or carburetor Check engine for leaks Check position of flywheel on crankshaft b 3 6 b 6 2 yes Check operation of switch shaft Short circuit wire chafed Function between contact spring and switch shaft contact Position F no connection Position 0 connection replace the wiring harness if necessary b 7 9 2 3 Ignition spark Engine runs ...

Page 61: ...t idle part and full load in response to external conditions e g operating at different altitudes and temperatures or with different fuel qualities the carburetor has no adjusting screws 8 1 Calibrating the Control Unit The control unit has to be calibrated if maximum engine speed is not reached or the control unit and or carburetor or solenoid valve have been replaced Remove the saw chain and gui...

Page 62: ... the STIHL MDG 1 for data transfer to the bluetooth stick on the computer The engine analyzer is supplied from the factory together with the diagnostic program on a data carrier for the computer The diagnostic program includes a database in which the data of different power tools is stored for the test run 1166RA225 TG Depending on the production date of the STIHL MDG 1 and the power tool to be te...

Page 63: ...rts in the reverse sequence 8 3 3 Testing Screw and Plug Connections and Switch Contact Carry out preparations b 8 3 1 A reliable connection is required for communications between the control unit switch unit and solenoid valve If communications between the control unit and solenoid valve are interrupted or faulty the control unit will not produce an ignition spark In the event of interference or ...

Page 64: ...e lever in direction of full throttle and set Master Control lever 1 to the lever 2 on the choke shaft must operate the microswitch arrow with an audible click If the microswitch is not operated by the lever 2 on the choke shaft fit a new lever if necessary b 13 5 7 If the microswitch does not work when it is operated install a new switch unit b 8 5 1166RA234 TG 2 1 8 3 4 Checking the Solenoid Val...

Page 65: ...black plug 1 to com ground socket and red plug 2 to Volt Ohm socket Set multimeter to diode test Test diode on switch unit 3 microswitch follow instructions supplied with multimeter 1166RA237 TG 1 3 2410RA238 TG 2 1 If the switch unit microswitch is in order and the Master Control lever is on the following values are obtained Measurement in forward direction specified value 0 3 V to 0 7 V Set the ...

Page 66: ... the specified values are not obtained Check wires for break and replace wiring harness if necessary b 8 3 6 Checking wires between control unit and diagnostic socket Connect test cable b 16 Measure resistance between terminal socket 1 with red wire and test cable s black plug 2 Specified value 10 Ω 1166RA271 TG 2 1 1166RA272 TG 1 2 Measure resistance between terminal socket 1 with black wire and ...

Page 67: ...s for break or contact between cable lug terminal socket replace switch unit if necessary b 8 5 Reassemble all other parts in the reverse sequence 8 4 Wiring Harness The wires of the M Tronic and the short circuit wire are combined in a wiring harness Removal and installation are described in the chapter on Wiring Harness with M Tronic Heating Removing and Installing b 7 10 1166RA275 TG 1 2 8 5 Sw...

Page 68: ...alve 1 in position Coat screws 2 with threadlocking adhesive b 16 Insert and tighten down the screws 2 firmly Position the connector 1 so that guide lug arrow faces the switch unit 2 Push connector 1 into solenoid valve s socket 3 as far as stop 1166RA279 TG 2 1 2 1166RA280 TG 2 1 3 Push the red wire 1 and black wire 2 into of the guides arrows in the switch unit 3 position the wires parallel to o...

Page 69: ... the solenoid valve above the collar sealing faces might otherwise be damaged Position the solenoid valve 1 so that it rests against the carburetor s stop 2 then push it carefully into the mounting bore Do not rotate the solenoid valve during this process its sealing face must not be damaged The solenoid valve 1 must be pushed squarely into the mounting bore 1166RA454 TG 2 1166RA455 TG 1 2 Positio...

Page 70: ...nic Troubleshooting Chart 8 7 1 Circuit Diagram 1 Stop switch 2 Choke switch 3 Diagnostic socket 4 Switch unit choke module 5 Solenoid valve in carburetor 6 Spark plug 7 Ignition lead 8 Control unit 1166RA427 TG 5 4 3 2 1 A B 7 6 8 ...

Page 71: ... detection and wiring harness electrically b 8 3 5 b 8 3 6 yes Mechanically in order Specified values obtained b 8 3 6 Look for fault in fuel system check engine for leaks b 13 11 b 13 5 b 6 2 Check the switch unit and wiring harness and clean or replace if necessary b 8 3 5 b 8 3 6 no yes no no Engine does not start Can the engine be started yes no Check the solenoid valve b 8 3 4 Specified value...

Page 72: ...and screw connections b 8 3 5 b 8 3 6 b 8 3 3 yes Mechanically in order Specified values obtained b 8 3 5 Look for fault in fuel system inlet needle lever spring diaphragm Check engine for leaks b 13 5 b 6 2 Check the switch unit and wiring harness and clean or replace if necessary b 8 3 5 b 8 3 6 yes no no Engine does not start in position engine flooded Can flooded engine be started in position ...

Page 73: ... down on power Look for fault in fuel system check engine for leaks b 13 5 b 6 2 Check the air filter and clean or replace if necessary b 13 1 Troubleshooting completed Power tool in order yes no Engine speed drops under load low power Calibrate the control unit b ...

Page 74: ... pairs of poles b 7 7 Combination in order Check the air gap between the control unit and flywheel b 7 3 Check correct combination of control unit flywheel yes Air gap in order Check ignition system with aid of Ignition System Troubleshooting Chart b 7 13 Set correct air gap b 7 3 no No spark yes no yes Can engine be started ...

Page 75: ...and or switch unit if necessary b 8 3 3 b 7 10 b 8 5 yes no no Engine stops suddenly no yes Check start detection microswitch activating lever and clean if necessary Replace switch unit b 8 5 Check start detection wiring harness plug and screw connections b 8 3 5 b 8 3 6 b 8 3 3 Mechanically in order Check the switch unit and wiring harness and clean or replace if necessary b 8 3 5 b 8 3 6 b 8 5 b...

Page 76: ... rpm Maximum engine speed less than 13 000 rpm Look for fault in fuel system check engine for leaks b 13 11 b 13 5 b 6 2 no Troubleshooting completed yes Check plug connections on control unit b 8 3 6 b 8 3 3 Connection and tightness of connector in order Check connectors replace insulated housing or wiring harnessif necessary b 7 10 no yes Check start detection wires plug and screw connections b ...

Page 77: ...d Before installing lubricate the rewind spring and starter post with STIHL special lubricant b 16 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 Clean all components 9 2 Rewind Starter Removing and Installing Take out the screw 1 and screws arrows Lift the hand guard a lit...

Page 78: ... Remove starter rope or remaining rope from rotor and install a new starter rope b 9 5 Inspect the rewind spring and replace if necessary b 9 7 Installing Lubricate full length of starter post with STIHL special lubricant b 16 Install starter rope in rope rotor b 9 5 Fit the rope rotor on the starter post so that the inner spring loop arrow engages the recess 1 Fit the cover washer 1 2 1166RA213 T...

Page 79: ...steady since it will otherwise spin back and may damage the rewind spring Pull out the twisted rope 1 in direction of starter grip and straighten it out Keep the rope 1 under tension and slowly release the rope rotor The starter grip must sit firmly in the rope guide bushing If it droops to one side Tension the rewind spring by one additional turn 1166RA217 TG 1 When the starter rope is fully exte...

Page 80: ...ow in the frame Fit the rewind spring 1 counterclockwise in the frame holding the windings steady in the process The procedure is otherwise the same as that for installing a new rewind spring Reassemble all other parts in the reverse sequence 9 8 Segment Remove the rewind starter b 9 2 Lift the segment 1 at the recess arrow and tab 2 until the pegs 3 are clear of the holes Inspect the segment repl...

Page 81: ...t into the bore until its groove arrow engages the housing rib 2 1 1166RA045 TG 1 1166RA084 TG 2 Reassemble all other parts in the reverse sequence 10 2 Antivibration Element on Oil tank Tank Housing Remove the stop buffer at the clutch side b 10 1 Take out the screw 1 Take out the screw 1 1166RA171 TG 1 1166RA172 TG 1 Remove the screws 1 from the underside of the machine pry the handlebar holder ...

Page 82: ...6RA175 TG 1 1 2 4 3 1 3 1166RA176 TG 2 Push pegs arrows into handlebar 1 and fit handlebar holder 2 in position Insert and tighten down the screws 1 firmly Insert and tighten down the screw 1 firmly bearing plug is now secure Reassemble all other parts in the reverse sequence 1166RA177 TG 1 2 1 1 1166RA178 TG 1 1166RA179 TG 10 3 AV Element on Fuel Tank Remove screw 1 from handlebar Take out the sc...

Page 83: ...ng stub arrow and screw it home as far as stop Lift the tank housing 1 until holes in bearing plug 2 line up Insert and tighten down the screw 3 firmly Insert and tighten down the screws 1 on the underside of the machine 1166RA186 TG 1 2 3 1 1 1166RA178 TG Lift the handlebar 1 sideways and position it in the guide arrow so that the peg 2 engages the seat in the crankcase On versions with handle he...

Page 84: ...ten down the screws 2 3 firmly Reassemble all other parts in the reverse sequence 10 4 1 Stop Buffer at Ignition Side Remove the ignition module control unit b 7 3 Remove the tank housing b 13 11 4 Ease the stop buffer 1 out of the bore Inspect the stop buffer and replace if necessary 2 1166RA191 TG 3 1 1166RA192 TG 1 Installing Use STIHL press fluid to make installation easier b 16 Position the s...

Page 85: ...stalling Place the handlebar in position Fit handlebar 1 between handlebar holder 2 and tank housing 3 push pegs arrows into handlebar 1 and place handlebar holder 2 in position Insert the screws and tighten them down firmly Lift the handlebar 1 sideways and position it in the guide arrow so that the peg 2 engages the seat in the crankcase 1166RA195 TG 2 3 1 2 1166RA187 TG 1 Position cover 1 with ...

Page 86: ...and remove the cover 2 1166RA180 TG 1 1 1 2 1166RA196 TG Machines with wrap around handlebar Take out the screws arrows and screw 1 Remove the elbow 2 Take off the cable retainer 1 and pull connector of wire 2 out of the heater switch 3 Pull the wire 2 out of the guide arrow 1166RA197 TG 2 1 1166RA198 TG 1 2 3 Pull wire 1 with pin and socket connector out of guides arrows and push insulating tube ...

Page 87: ... 2 2 1166RA201 TG 1 3 Installing Insert and tighten down the screw 1 firmly Push on the plastic sleeve 2 until it snaps into position Push home the handlebar stiffener 3 as far as stop Place the handlebar in position Fit handlebar 1 between handlebar holder 2 and tank housing 3 push pegs arrows into handlebar 1 and place handlebar holder 2 in position Insert the screws and tighten them down firmly...

Page 88: ...05 TG 2 4 3 1 1166RA206 TG 1 2 Wires must be properly seated in the guides Position cover 1 with bosses in holes in handlebar 2 making sure the tab 3 engages the groove arrow check that wires are not pinched Insert and tighten down the screws 4 firmly 1166RA188 TG 1 4 3 4 2 Machines with wrap around handlebar Position elbow 1 with bosses in holes in handlebar 2 making sure the tab 3 engages the gr...

Page 89: ...at the same time Pry switch shaft 1 out of pivot mount arrow and pull it out of the lateral pivot mount take care not to damage the short circuit wire All models Pull the short circuit wire 1 out of the guides arrows and push the ring terminal 2 out sideways 1166RA292 TG 1 2 1166RA293 TG 1 1166RA294 TG 1 2 Inspect the switch shaft and replace if necessary Inspect the contact spring and retainer re...

Page 90: ... 1 short circuit wire 2 and M Tronic wire 3 must be seated in the guides 4 5 6 push them into the guides if necessary loops arrows allow for movement 1 4 2 5 6 6 3 1166RA440 TG Move the switch shaft 1 in direction of STOP and hold it there Push the retainer 2 into the guides in the tank housing 3 until the locking tabs arrows engage position lever 4 behind lever 5 on choke shaft at the same time I...

Page 91: ...ary Installing Models with M Tronic Attach the torsion spring 1 between lever 2 and throttle trigger 3 note installed position arrow 1166RA323 TG 1 2 4 3 1166RA325 TG 1 2 3 Fit the throttle trigger 1 in the rear handle so that lever 2 engages over the switch lever s cam and the tongue arrow is within the rear handle the holes must be in alignment Use a punch 3 to center the throttle trigger 1 On v...

Page 92: ...r 2 downwards and attach leg 1 of torsion spring Fit the handle molding and push it down until it snaps into position lockout lever 2 may pop out Check operation Squeeze trigger all the way the throttle lever on the carburetor must then be in the full throttle position It should not be possible to move it any further in the open direction Reassemble all other parts in the reverse sequence 11 3 Thr...

Page 93: ... grommet 2 and push throttle rod 1 into the grommet 2 so that the end with the hook arrow faces the carburetor then position retainer 3 against guides arrows 1166RA333 TG 2 1 1166RA334 TG 3 1 2 Models without M Tronic Short circuit wire 1 must be seated in the guide 2 loop arrow allows for movement 1166RA299 TG 1 2 Models with M Tronic Ground wire 1 short circuit wire 2 and M Tronic wire 3 must be...

Page 94: ...further in the open direction Reassemble all other parts in the reverse sequence 11 3 1 Choke Rod Models without M Tronic Remove the filter base b 13 3 Pry the choke rod 1 out of the switch shaft arrow and disconnect it from lever on choke shaft 2 Inspect the choke rod and replace if necessary 1166RA336 TG 1 2 Installing Attach choke rod 1 to lever 2 on choke shaft so that its bent end arrow faces...

Page 95: ...in the oil tank b 1 1 Remove the clutch b 4 2 Remove the brake band b 5 2 Remove the oil pump b 12 3 Remove the oil suction hose 1 together with the pickup body Check the oil suction hose and pickup body and replace if necessary Fit the pickup body b 12 1 Installing Coat groove in fuel suction hose with STIHL press fluid b 16 Push the oil suction hose 1 pickup body first through the housing bore a...

Page 96: ...ng 1 in the bore arrow Line up the oil pump 1 so that the stub 2 engages the oil suction hose 3 and stub 4 slips into the sealing ring 5 Coat stubs and sealing ring with STIHL press fluid b 16 1166RA345 TG 1 1166RA346 TG 1 2 3 5 4 Push oil pump 1 into position as far as stop Fit the screws 2 and tighten them down firmly Push the worm fully home Push the cover washer 1 into position Installed posit...

Page 97: ...d in the housing the adjusting screw can be set to maximum oil flow a 1166RA439 TG 1166RA426 TG 1 12 4 Valve A valve is installed in the housing wall to keep internal tank pressure equal to atmospheric pressure The valve must be replaced if it is faulty Open the oil tank cap and drain the oil tank b 1 1 Use a 6 mm drift to carefully drive the valve out of its seat in the housing and into the oil t...

Page 98: ...that the stub arrow engages the opening in the filter base and the locking tab 1 snaps into place Reassemble all other parts in the reverse sequence 13 3 Filter Base Remove the baffle b 13 2 Unscrew the nuts 1 To reduce the risk of dirt particles getting into the intake port set switch shaft 2 to cold start set it to on M Tronic machines Remove the filter base 3 from the studs 1 1166RA302 TG 1 1 3...

Page 99: ...heating element 2 and put it to one side 1166RA306 TG 1 2 Take out the screw 1 and pull the thermocouple s wire 2 out of the guide arrow Models with M Tronic Take out the screw 1 and pull the M Tronic s red wire 2 out of the guides arrows Disconnect spade terminal 1 from the contact spring 2 and pull the M Tronic s black wire 2 out of the guides arrows 2 1 1166RA307 TG 1166RA308 TG 1 2 1166RA309 T...

Page 100: ...it the carburetor 1 over the studs arrows and push the stub 2 into the impulse hose 3 at the same time Make sure the sleeve 4 is in place 1 1166RA314 TG 2 3 1 1166RA315 TG 4 2 3 Use STIHL press fluid to make installation easier b 16 Grip tab 2 on elbow connector with fuel suction hose 1 to push it into fuel suction hose 3 so that the guide lug engages between the ribs arrow the fuel suction hose i...

Page 101: ...ide faces up and the wire locates in the guide arrow Insert and tighten down the screw 2 firmly Models without M Tronic Use STIHL press fluid to make installation easier b 16 1166RA320 TG 1 2 2 1166RA366 TG 1 4 3 Hold the grommet 1 so that the extensions 2 3 and the peg 4 match the openings arrows in the tank housing Slide the grommet 1 between the handlebar cover and tank housing then push it int...

Page 102: ... b 13 5 5 Test the tank vent if necessary b 13 10 1 After completing the test push the ring 1 to the left to vent the system and then pull the fuel hose off the carburetor Install the carburetor b 13 4 Reassemble all other parts in the reverse sequence 1 1166RA241 TG 2 13 5 Servicing the Carburetor 13 5 1 Disassembling and Cleaning the Carburetor Cleaning the carburetor in an ultrasonic bath is no...

Page 103: ... 13 4 Check the sleeve remove and replace it if necessary All models Take out the screws 1 and remove the end cover 2 If the gasket and metering diaphragm are stuck to the carburetor remove them very carefully Carefully separate the metering diaphragm 1 and gasket 2 The diaphragm material is subjected to continuous alternating stresses and eventually shows signs of fatigue i e the diaphragm distor...

Page 104: ...247 TG 1 2 Pull out the inlet needle 1 and spring 2 check and replace if necessary If there is an annular indentation arrow on the sealing cone of the inlet needle fit a new inlet needle Installing Fit the inlet needle 1 Fit the spring 2 in the bore 1166RA248 TG 1 2 165RA348 TG 1166RA249 TG 1 2 Position the inlet control lever 1 with spindle 2 on the spring arrow first then slide the inlet control...

Page 105: ...mp diaphragm 1 and gasket 2 Inspect the end cover and replace if necessary The diaphragm material is subjected to continuous alternating stresses and eventually shows signs of fatigue i e the diaphragm distorts and swells and has to be replaced Check the pump diaphragm for signs of damage and wear Install a new gasket 1166RA252 TG 1 2 1 1 1 3 1166RA253 TG 2 1 Check fuel strainer for contamination ...

Page 106: ... body Check that the pump diaphragm and gasket are properly seated Insert and tighten down the screws 2 firmly Versions with carburetor heating Push the wire 1 into the guides arrows 1166RA258 TG 2 1 2 2 2 1166RA260 TG 1 Move the end cover 1 back and forth until its pegs engage the holes in the carburetor body Fit the thermostatic switch 2 so that it engages the recesses arrows Check that the pump...

Page 107: ...t on models without M Tronic fit lever with lobe on its tip arrow Push the lever 1 onto the choke shaft so that it engages the flats on the end of the shaft Insert and tighten down the screw 2 firmly Reassemble all other parts in the reverse sequence 1166RA263 TG 2 1 1166RA264 TG 1 2 13 5 8 Lever on Choke Shaft Switch Unit Models with M Tronic Remove the carburetor b 13 4 Troubleshooting b 8 3 Car...

Page 108: ...out switch unit for greater clarity Position of special screw 1 must not be changed changing the factory setting will cause engine running problems If solenoid valve 2 has been turned out of position turn it back counterclockwise as far as stop arrow then test the solenoid valve 2 b 8 3 4 In the event of problems test the M Tronic b 8 3 1166RA270 TG 2 1 13 7 Adjusting the Carburetor Models without...

Page 109: ... speed screw L as far as stop Continue with the high speed screw H High speed screw Screw the puller 1 5910 890 4500 about 5 turns counterclockwise into the limiter cap left hand thread Do not turn the puller 1 any further the high speed screw H may otherwise be damaged 3443RA320 TG 1 1 1166RA285 TG Check position of limiter cap If necessary use the puller to turn the limiter cap counterclockwise ...

Page 110: ...4 through the pre installed limiter caps of high speed screw H and low speed screw L Starting with the high speed screw H against its seat open it 1 1 2 turns counterclockwise Starting with the low speed screw L against its seat open it 1 full turn Go to Setting b 13 8 2 1 1166RA288 TG 13 8 2 Setting Insert screwdriver 5910 890 2304 through the grommet and the pre installed limiter caps of high sp...

Page 111: ...or the standard setting Always perform the following steps before carrying out any adjustments Troubleshooting b 3 6 Check chain tension and adjust if necessary Inspect the spark arresting screen if fitted and clean or replace if necessary b 3 7 or b 6 1 Check the air filter and clean or replace if necessary b 13 1 1 1166RA290 TG 1 Standard setting with limiter caps Shut off the engine Turn the hi...

Page 112: ... adjusting screws only very slightly Even minor adjustments can noticeably affect engine running behavior If the setting is made too lean there is a risk of engine damage as a result of lack of lubrication and overheating Readjust carburetor to Standard Setting after returning from high altitude 13 9 Manifold A damaged intake manifold can cause engine running problems b 3 7 Troubleshooting b 3 6 o...

Page 113: ... the tank housing against the manifold and hold it there Grip the ends of the string 2 and pull the manifold flange 1 through the opening Remove the string Position the manifold flange 1 its recesses arrows must locate against the studs 2 Fit the washer 3 and push the sleeve 4 into the manifold flange 1 Install the carburetor b 13 4 Reassemble all other parts in the reverse sequence 1 2 1166RA352 ...

Page 114: ... hose Push the ring 3 to the left and connect the pump 4 0000 850 1300 to the hose 2 create a vacuum in the fuel 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 housing b 13 10 or b 13 11 4 1166RA356 TG 4 3 2 1 Pressure test Push ring 1 to the right pressurize...

Page 115: ...requirements b 1 1 Open the tank cap Use hook 5910 893 8800 to remove the pickup body 1 from the fuel tank Do not overstretch the fuel hose Pull off the pickup body 1 check it and replace if necessary Reassemble in the reverse sequence 13 11 2 Fuel Suction Hose in Tank Housing Open the tank cap Remove the carburetor b 13 4 Remove the pickup body b 13 11 1 Pry fuel suction hose 1 out of bore and pu...

Page 116: ...ow connector 2 on the nipple 3 so that lug arrow faces to the rear in the direction of the throttle shutter Install the carburetor b 13 4 Reassemble all other parts in the reverse sequence 13 11 4 Tank Housing Drain the fuel tank b 1 1 Remove the carburetor b 13 4 Remove the handle molding and lockout lever b 11 2 Remove the stop buffer at the clutch side b 10 1 Remove the ignition module control ...

Page 117: ...e handlebar b 10 5 Models with heating b 10 5 1 Versions with handle and carburetor heating Transfer heating element in rear handle b 14 5 Transfer the heater switch b 14 4 Transfer heating element wiring b 14 8 All models Check the stop buffer 1 at the ignition side and replace if necessary b 10 4 1 1166RA414 TG 1 Installing Push the tank housing 1 with handlebar between the two halves of the cra...

Page 118: ...ne up Insert and tighten down the screw 3 firmly 1 1166RA417 TG 1166RA418 TG 1166RA419 TG 2 1 3 Fit bearing plug 1 in position Coat the screw 2 with threadlocking adhesive fit it and tighten it down firmly b 16 Install the stop buffer at the clutch side b 10 1 Install the ignition module control unit b 7 3 Fit wiring harness at ignition side b 7 9 M Tronic heating b 7 10 Install the carburetor b 1...

Page 119: ...chart b 14 2 Remove the air filter b 13 1 Set the ohmmeter to measuring range Ω Clip one of the two test leads to a nut on the filter base and the other to a cylinder fin If the system is in good condition the ohmmeter will indicate a value of about 10 Ω in measuring range Ω If the reading obtained is outside this tolerance test each component separately 14 1 2 Testing the Heating Element Remove t...

Page 120: ...with the aid of the Troubleshooting Chart b 14 2 Remove the carburetor b 13 4 1166RA423 TG 2 1 3 Take out the screws 1 and remove the thermostatic switch 2 Do not loosen the fourth screw 3 end cover 4 pump diaphragm and gasket remain fixed in position Installing Push the wire 1 into the guides arrows 1166RA424 TG 1 2 1 1 3 4 1166RA260 TG 1 Fit the thermostatic switch 1 so that it engages the reces...

Page 121: ...ment at temperature 20 C 68 F Replace thermostatic switch b 14 1 3 no Replace heating element b 14 1 2 Carburetor heating element in order yes G Generator 1 Rear handle 2 Handlebar 3 Heater switch 4 Thermostatic switch 5 Heating element carburetor 0001RA505 TG G 1 4 5 2 3 Resistance approx 8 Ω Circuit Diagram ...

Page 122: ...he connecting wire and the rear handle heating element wire Carburetor heating Take out the screw and remove the thermostatic switch wire then refit the screw and tighten it down firmly b 13 4 All electrical components of the handle heating system are connected in series with the ohmmeter If the system is in order the ohmmeter will indicate a value of about 10 Ω in measuring range Ω 1166RA372 TG 1...

Page 123: ...cessary Installing Slide the multiple tab 1 onto the heater switch 2 so that the nib 3 engages the slot To ensure the switch position is correct slide the heater switch 1 with multiple tab 2 into the tank housing bore so that the nib 3 engages the recess arrow 1166RA376 TG 2 1 1166RA377 TG 2 1 3 1166RA378 TG 1 2 3 Fit the washer 1 screw on the nut 2 and tighten it down firmly Connect the flag term...

Page 124: ... this range install a new heating element Heating element does not operate even though resistance measurement is ok Test the generator and heater switch b 14 7 b 14 4 Check connecting wires to handlebar heating and replace if necessary b 14 8 Installing Position the new heating element 1 so that it butts against the angled edge arrow and locates in rear handle s slot arrow make sure it is complete...

Page 125: ...ing is outside this range test the handlebar handlebar heating element directly on the connecting wires Separate pin and socket connector on handlebar b 10 5 1 Clip one test lead to the connector pin of wire 1 and the other test lead to the heater switch contact sleeve If the heating elements are in good condition the ohmmeter will indicate a value of about 6 4 Ω measured value 6 0 8 0 Ω in measur...

Page 126: ...or is properly seated Fit the screws and tighten them down firmly Push insulating tube onto generator wire Reconnect the pin and socket connector 1 and center the insulating tube 2 on the connector 1 1166RA392 TG 1 1166RA393 TG 1 2 Push the insulating tube 1 with pin and socket connector into the guide arrow Push the generator wire 1 into the guides arrows loop 2 allows for movement The compensati...

Page 127: ...re resistance of individual heating elements with ohmmeter Separate the screw connection to the thermostatic switch b 13 4 no yes Set switch to on yes Resistance of rear handle heating element about 1 6 Ω Check rear handle heating element In good condition Flat against handle housing Heater switch on F no no no Install new rear handle heating element b 14 5 Replace generator b 14 7 yes yes yes no ...

Page 128: ... b 10 5 1 Test handlebar heating element Resistance about 6 4Ω Check the heater switch contact sleeve against switch housing Closed about 0Ω Open Circuit interrupted b 14 3 Reconnect connector to thermostatic switch b 13 4 no no Replace handlebar b 10 5 1 Replace heater switch b 14 4 yes yes 1 2 3 ...

Page 129: ...ng 0 5 Switch faulty Replace switch Heating element in rear handle Connector on wire from heating element Connector on wire from heating element 1 6 1 5 2 0 Heating element OK Break in wire heating element damaged Replace heating element or repair insulation 0 Short circuit damaged insulation Heating element in handlebar Connector on wire from handlebar heating element Connector on wire from handl...

Page 130: ...pec Actual Cause Remedy Generator Connector on generator wire Ground 0 6 0 5 1 Generator OK Break in wire generator damaged Install new generator 0 Short circuit damaged insulation repair insulation G Generator 1 Rear handle 2 Handlebar 3 Heater switch 4 Thermostatic switch 5 Heating element carburetor 0001RA505 TG G 1 4 5 2 3 ...

Page 131: ...the guides connecting wire 1 goes to the handlebar and is underneath the connecting wire 2 on the rear handle Push back the insulating tube 3 in the direction of connecting wire and separate the pin and socket connector Remove and inspect the connecting wire replace it if necessary Installing Fit the insulating tube 1 on the connecting wire 2 Reconnect pin and socket of wire 3 and handlebar connec...

Page 132: ... carburetor b 13 4 Pull the retainer with switch shaft out of the guide and put it to one side b 11 1 1 Take out the screws 1 and remove the cover 2 Connecting Wire between Rear Handle Heating Element and Handlebar Pull connecting wire 1 with pi and socket connector out of the guides arrows and put it to one side 1 1 2 1166RA196 TG 1 1166RA402 TG Connecting Wire between Rear Handle Heating Element...

Page 133: ...itch and push it into the guides arrows Pull the connecting wire 2 out through the grommet 3 in direction of handlebar until there are no more loops the wire must not be under tension Push the generator connecting wire 1 into the guides arrows and then hook it tightly around the lug 2 connecting wire to handlebar and must be hooked in place and underneath the generator wire 1166RA407 TG 1 2 3 1166...

Page 134: ... connectors into the guides arrows Push the wires into the guide between the rib and handle heating so that the connecting wire to the handlebar is underneath the generator connecting wire Reassemble all other parts in the reverse sequence 1166RA410 TG 1 1 ...

Page 135: ...kage test 1122 025 2200 Leakage testing decompression valve 2 Sealing plate 0000 855 8106 Testing engine for leaks 3 Installing tool 0000 890 2201 Installing rope guide bushing 4 Clamping strap 0000 893 2600 Compressing the piston rings 5 Locking strip 0000 893 5903 Blocking the crankshaft 6 Screwdriver bit T 27 x 125 0812 542 2104 Removing and installing spline socket screws with electric or pneu...

Page 136: ...tion system 23 Torque wrench 5910 890 0302 0 5 to 18 Nm 24 Torque wrench 5910 890 0312 6 to 80 Nm 25 Installing tool 12 5910 890 2212 Installing hookless snap rings in piston 26 Screwdriver 5910 890 2304 Adjusting carburetor through limiter caps 27 Screwdriver bit T 27 x 150 5910 890 2400 IS P screws 28 Hook 5910 890 2800 Detaching springs on clutch shoes 29 Punch down tool 5910 890 4000 Fitting e...

Page 137: ...pring in fan housing 4 STIHL press fluid OH 723 0781 957 9000 Rubber components AV buffers 5 Medium strength threadlocking adhesive Loctite 242 0786 111 2101 6 High strength threadlocking adhesive Loctite 270 0786 111 2101 7 High strength threadlocking adhesive up to 250 C Loctite 272 0786 111 2101 8 Standard commercial solvent based degreasant containing no chlorinated or halogenated hydrocarbons...

Page 138: ...englisch english 0455 758 0123 VA0 G13 Printed in Germany ...

Search results

Summary of Contents for MS 661

Reviews:

Related manuals for MS 661

Brands by name

Popular brands

Stihl MS 661, Manual

Search results

Summary of Contents for MS 661

Reviews:

Related manuals for MS 661

Brands by name

Popular brands