Product Instruction Manual
Page 12
... you might be damaged or removed. Operating instructions Warning! Always stop switch to 0 or STOP. Warning! To reduce the risk of the cylinder, spark plug) become hot during normal operation may occur if the throttle is depressed for more than a few seconds when the chain is ...saw down sitting on concrete, metal, bare ground or solid wood (e.g. Such objects may be cutting asbestos, immediately contact your STIHL servicing dealer only. 10 MS 311, MS 391 To reduce the risk of asbestos-containing products have any reason to kickback. It can cause severe or fatal injury, ...
... you might be damaged or removed. Operating instructions Warning! Always stop switch to 0 or STOP. Warning! To reduce the risk of the cylinder, spark plug) become hot during normal operation may occur if the throttle is depressed for more than a few seconds when the chain is ...saw down sitting on concrete, metal, bare ground or solid wood (e.g. Such objects may be cutting asbestos, immediately contact your STIHL servicing dealer only. 10 MS 311, MS 391 To reduce the risk of asbestos-containing products have any reason to kickback. It can cause severe or fatal injury, ...
Product Instruction Manual
Page 13
...! English Kickback: Kickback may interfere with a damaged or improperly mounted cylinder shroud or a damaged/deformed muffler shell. To reduce the risk of... to the heat from the emission of control. pushback, - This may cause serious or fatal injury. Some STIHL power tools are : - stay clean and need no service or maintenance. Since a muffler with a catalytic ... contributes to begin a plunge or boring cut wood can cause serious personal injury. kickback, - MS 311, MS 391 11 Your catalytic converter is furnished with any time the chain is incorrectly used to reduce...
...! English Kickback: Kickback may interfere with a damaged or improperly mounted cylinder shroud or a damaged/deformed muffler shell. To reduce the risk of... to the heat from the emission of control. pushback, - This may cause serious or fatal injury. Some STIHL power tools are : - stay clean and need no service or maintenance. Since a muffler with a catalytic ... contributes to begin a plunge or boring cut wood can cause serious personal injury. kickback, - MS 311, MS 391 11 Your catalytic converter is furnished with any time the chain is incorrectly used to reduce...
Product Instruction Manual
Page 31
...The chain brake will operate only if it serviced and maintained regularly by trained personnel, such as your STIHL servicing dealer, at idle speed, engage the chain brake (push hand guard toward bar nose). It is...Check operation of the position s (summer operation) The chain brake is necessary to overheating 0001BA003 KN MS 311, MS 391 29 Chain brake maintenance Remove shroud N Move the Master Control lever to full throttle for no ...the chain must be free from around the cylinder and circulates around the carburetor - this helps prevent carburetor icing. The hand guard must not...
...The chain brake will operate only if it serviced and maintained regularly by trained personnel, such as your STIHL servicing dealer, at idle speed, engage the chain brake (push hand guard toward bar nose). It is...Check operation of the position s (summer operation) The chain brake is necessary to overheating 0001BA003 KN MS 311, MS 391 29 Chain brake maintenance Remove shroud N Move the Master Control lever to full throttle for no ...the chain must be free from around the cylinder and circulates around the carburetor - this helps prevent carburetor icing. The hand guard must not...
Product Instruction Manual
Page 44
... spring tension by another half-turn . risk of children and other unauthorized persons. 42 MS 311, MS 391 STIHL BioPlus, completely fill the chain oil tank. N If you use a biological chain and bar lubricant, e.g. It must be possible to the cylinder fins and air filter. N Run the engine until the carburetor is dry - N Store the...
... spring tension by another half-turn . risk of children and other unauthorized persons. 42 MS 311, MS 391 STIHL BioPlus, completely fill the chain oil tank. N If you use a biological chain and bar lubricant, e.g. It must be possible to the cylinder fins and air filter. N Run the engine until the carburetor is dry - N Store the...
Product Instruction Manual
Page 50
...intervals apply to 20 hours of operation. 4) not in all versions, market-specific X X X X X X X X X X 48 MS 311, MS 391 If you only use the saw occasionally, extend the intervals accordingly. chain must not rotate X X Readjust idle Spark Plug Readjust electrode ...first 139 hours of operating, then every 150 hours Check X Chain catcher Replace Safety labels Replace 1) STIHL recommends a STIHL servicing dealer. 2) see chapter on "Chain Brake" 3) Firmly tighten down the cylinder base screws of professional saws (3.4 kW or more) after each refueling stop weekly monthly every 12 ...
...intervals apply to 20 hours of operation. 4) not in all versions, market-specific X X X X X X X X X X 48 MS 311, MS 391 If you only use the saw occasionally, extend the intervals accordingly. chain must not rotate X X Readjust idle Spark Plug Readjust electrode ...first 139 hours of operating, then every 150 hours Check X Chain catcher Replace Safety labels Replace 1) STIHL recommends a STIHL servicing dealer. 2) see chapter on "Chain Brake" 3) Firmly tighten down the cylinder base screws of professional saws (3.4 kW or more) after each refueling stop weekly monthly every 12 ...
Product Instruction Manual
Page 53
... the section "Safety Precautions and Working Techniques". Category A = 300 hours B = 125 hours C = 50 hours Engine STIHL single cylinder two-stroke engine MS 311 Displacement: 3.60 cu. in. (59.0 cm3) Bore: 1.85 in. (47 mm) Stroke: 1.34 in . (1.6 mm) MS 311, MS 391 51 Specifications EPA / CEPA The Emission Compliance Period referred to on the Emissions Compliance Label...
... the section "Safety Precautions and Working Techniques". Category A = 300 hours B = 125 hours C = 50 hours Engine STIHL single cylinder two-stroke engine MS 311 Displacement: 3.60 cu. in. (59.0 cm3) Bore: 1.85 in. (47 mm) Stroke: 1.34 in . (1.6 mm) MS 311, MS 391 51 Specifications EPA / CEPA The Emission Compliance Period referred to on the Emissions Compliance Label...
Parts Diagram
Page 4
... 20 1135 145 9002 21 1140 140 8100 22 9039 448 0656 23 9022 341 0980 24 0783 830 2000 Qty Description 1 Cylinder with piston Ø 47 mm (1,2) ☐ 3 - 6 1 Cylinder with piston Ø 49 mm (3,4) ☐ 5 - 8 1 Piston Ø 47 mm (1,2) ☐ 4 - 6 2 Piston ring Ø 47x1.2 mm (1,2) 1 Piston pin 12x8x33 2 Snap ring 12x1... Cert. I.D. 1140/01 USA ☐ 20 - 22 2 Plug 1 spark arresting screen (2,4) 1 Self-tapping screw M4x9.6 (2,4) 2 Spline screw IS-M5x16 1 Tube of sealant Dirko HT red (B) (1) MS 311, (2) MS 311-Z, (3) MS 391, (4) MS 391-Z MS 311, MS 391 4 SCS 01-2010 3.29
... 20 1135 145 9002 21 1140 140 8100 22 9039 448 0656 23 9022 341 0980 24 0783 830 2000 Qty Description 1 Cylinder with piston Ø 47 mm (1,2) ☐ 3 - 6 1 Cylinder with piston Ø 49 mm (3,4) ☐ 5 - 8 1 Piston Ø 47 mm (1,2) ☐ 4 - 6 2 Piston ring Ø 47x1.2 mm (1,2) 1 Piston pin 12x8x33 2 Snap ring 12x1... Cert. I.D. 1140/01 USA ☐ 20 - 22 2 Plug 1 spark arresting screen (2,4) 1 Self-tapping screw M4x9.6 (2,4) 2 Spline screw IS-M5x16 1 Tube of sealant Dirko HT red (B) (1) MS 311, (2) MS 311-Z, (3) MS 391, (4) MS 391-Z MS 311, MS 391 4 SCS 01-2010 3.29
User Manual
Page 2
... 28 9.2 AV Spring on Oil Tank 57 6.2.2 Vacuum Test 29 9.3 AV Spring on 6.4 Shroud 31 Front Handle 58 2.1 Engine 5 6.5 Cylinder / Crankshaft 32 9.5 Stop Buffer at 2.2 Fuel System 5 6.6 Bearings / Crankshaft 35 Clutch Side 59 2.3 Ignition System 5 6.7 Piston 36 ... 8.4 Rope Rotor 52 8.5 Starter Rope / Grip 53 8.6 Tensioning the Rewind Spring 54 8.7 Replacing the Rewind Spring 55 RA_542_00_01_01 MS 311, MS 391 q © ANDREAS STIHL AG & Co. Control Levers 61 3.1 Clutch 3.2 Chain Drive, Chain Brake, Chain Tensioner 3.3 Chain Lubrication 3.4 Rewind Starter ...
... 28 9.2 AV Spring on Oil Tank 57 6.2.2 Vacuum Test 29 9.3 AV Spring on 6.4 Shroud 31 Front Handle 58 2.1 Engine 5 6.5 Cylinder / Crankshaft 32 9.5 Stop Buffer at 2.2 Fuel System 5 6.6 Bearings / Crankshaft 35 Clutch Side 59 2.3 Ignition System 5 6.7 Piston 36 ... 8.4 Rope Rotor 52 8.5 Starter Rope / Grip 53 8.6 Tensioning the Rewind Spring 54 8.7 Replacing the Rewind Spring 55 RA_542_00_01_01 MS 311, MS 391 q © ANDREAS STIHL AG & Co. Control Levers 61 3.1 Clutch 3.2 Chain Drive, Chain Brake, Chain Tensioner 3.3 Chain Lubrication 3.4 Rewind Starter ...
User Manual
Page 7
... 5x16 Spiked bumper / engine housing 4.0 M 4x12 Manifold/cylinder 4.0 P 6x21.5 Bearing plug / engine housing 6.0 M 5x16 Bearing plug/cylinder 10.0 P 5x20 Fan housing / engine housing 4.0 P ...cylinder, stage 1 4.0 M 6x25 Engine housing / cylinder, stage 2 12.0 D 4x18 Oil pump 4.0 M 5x16 Muffler / cylinder 10.0 M 8x1 Flywheel/crankshaft 33.0 M 5 Carburetor/collar stud 3.5 P 4x14 Pre-separator / engine housing 2.0 P 4x12 Cover plate/fan housing 2.0 M 14x1.25 Spark plug 25.0 D 4x18 Ignition module / engine pan 4.0 1) 3) 4) 3) 3) 3) 1) 3) 5) 3) 6 MS 311, MS...
... 5x16 Spiked bumper / engine housing 4.0 M 4x12 Manifold/cylinder 4.0 P 6x21.5 Bearing plug / engine housing 6.0 M 5x16 Bearing plug/cylinder 10.0 P 5x20 Fan housing / engine housing 4.0 P ...cylinder, stage 1 4.0 M 6x25 Engine housing / cylinder, stage 2 12.0 D 4x18 Oil pump 4.0 M 5x16 Muffler / cylinder 10.0 M 8x1 Flywheel/crankshaft 33.0 M 5 Carburetor/collar stud 3.5 P 4x14 Pre-separator / engine housing 2.0 P 4x12 Cover plate/fan housing 2.0 M 14x1.25 Spark plug 25.0 D 4x18 Ignition module / engine pan 4.0 1) 3) 4) 3) 3) 3) 1) 3) 5) 3) 6 MS 311, MS...
User Manual
Page 17
... Decompression valve is not closed Close, check and replace decompression valve if necessary Engine overheating Insufficient cylinder cooling. Carburetor - 3.7 Engine Always check and, if necessary, repair the following parts before looking for faults on cylinder very dirty Thoroughly clean all cooling air openings and the cylinder fins 16 MS 311, MS 391 Fuel system - Air filter -
... Decompression valve is not closed Close, check and replace decompression valve if necessary Engine overheating Insufficient cylinder cooling. Carburetor - 3.7 Engine Always check and, if necessary, repair the following parts before looking for faults on cylinder very dirty Thoroughly clean all cooling air openings and the cylinder fins 16 MS 311, MS 391 Fuel system - Air filter -
User Manual
Page 18
Troubleshooting, b 3.1 - Unscrew the spark plug. 4903RA001 TG : The locking strip (1) 0000 893 5903 must butt against the cylinder wall (arrow) as shown. - Pull the clutch shoes off the spark plug. - If the clutch is noticeably worn, replace all parts, b 14 - not ... into the spark plug hole, wide end first, so that the clutch has a left-hand thread. Clean all three clutch shoes at the same time - MS 311, MS 391 17 Remove the shroud, b 6.4. - 4. Replace any damaged parts. Clutch - Note that "OBEN-TOP" faces up. 4903RA002 TG : Apply wrench to remove ...
Troubleshooting, b 3.1 - Unscrew the spark plug. 4903RA001 TG : The locking strip (1) 0000 893 5903 must butt against the cylinder wall (arrow) as shown. - Pull the clutch shoes off the spark plug. - If the clutch is noticeably worn, replace all parts, b 14 - not ... into the spark plug hole, wide end first, so that the clutch has a left-hand thread. Clean all three clutch shoes at the same time - MS 311, MS 391 17 Remove the shroud, b 6.4. - 4. Replace any damaged parts. Clutch - Note that "OBEN-TOP" faces up. 4903RA002 TG : Apply wrench to remove ...
User Manual
Page 20
... locking strip from the cylinder. - Lubricate the needle cage and crankshaft stub, b 14 1 165RA029 TG 80% ! 100% - If there are signs of serious wear on to the crankshaft stub and tighten down the hexagon (arrow) firmly - Install the clutch drum. Clean the needle cage and crankshaft stub, b 14 - MS 311, MS 391 19 Reassemble...
... locking strip from the cylinder. - Lubricate the needle cage and crankshaft stub, b 14 1 165RA029 TG 80% ! 100% - If there are signs of serious wear on to the crankshaft stub and tighten down the hexagon (arrow) firmly - Install the clutch drum. Clean the needle cage and crankshaft stub, b 14 - MS 311, MS 391 19 Reassemble...
User Manual
Page 28
...MS 311, MS 391 27 Remove and install the spark arresting screen - Hold the machine upright. 1 1 2 : Inspect and clean the sealing faces (arrows) and remove any gasket residue. Troubleshooting, b 3.7 - Remove the shroud, b 6.4 1 Before removing the muffler, set the piston to top dead center to ensure that the warts (arrows) point towards the cylinder...for faults on the engine. 0001RA080 TG 0001RA076 TG - Always replace components with the warts (arrows) against the cylinder exhaust port. 22 4903RA056 TG 0001RA081 TG : Pry the plug (1) out of the gasket and fit the ...
...MS 311, MS 391 27 Remove and install the spark arresting screen - Hold the machine upright. 1 1 2 : Inspect and clean the sealing faces (arrows) and remove any gasket residue. Troubleshooting, b 3.7 - Remove the shroud, b 6.4 1 Before removing the muffler, set the piston to top dead center to ensure that the warts (arrows) point towards the cylinder...for faults on the engine. 0001RA080 TG 0001RA076 TG - Always replace components with the warts (arrows) against the cylinder exhaust port. 22 4903RA056 TG 0001RA081 TG : Pry the plug (1) out of the gasket and fit the ...
User Manual
Page 29
... - Pry out the plugs. - This can be checked through the spark plug hole. - The sealing plate must completely fill the space between the cylinder exhaust port and muffler and tighten down firmly. : Fit the sealing plate (1) 0000 855 8107 between the two screws. - Always perform the vacuum test... the pressure test. Remove the shroud, b 6.4 - Set the piston to part or full throttle is not smooth. Remove the carburetor, b 12.5 28 MS 311, MS 391 Pull off the boot and unscrew the spark plug. - Remove the decompression valve, b 6.9 0001RA083 TG - Do not refit old plugs, always fit ...
... - Pry out the plugs. - This can be checked through the spark plug hole. - The sealing plate must completely fill the space between the cylinder exhaust port and muffler and tighten down firmly. : Fit the sealing plate (1) 0000 855 8107 between the two screws. - Always perform the vacuum test... the pressure test. Remove the shroud, b 6.4 - Set the piston to part or full throttle is not smooth. Remove the carburetor, b 12.5 28 MS 311, MS 391 Pull off the boot and unscrew the spark plug. - Remove the decompression valve, b 6.9 0001RA083 TG - Do not refit old plugs, always fit ...
User Manual
Page 33
...the screws (arrows). : Pull the crankshaft (1) out of the cylinder. - Remove the shroud, b 6.4 1 - Pull off the boot and unscrew the spark plug, - Remove the filter base, b 12.3 - Remove the cylinder with piston out of the bearing seats (arrows). : Carefully pull... Cylinder / Crankshaft 1 - Remove the manifold, b 12.9 - Remove the muffler, b 6.1 : Use the lug (arrow) to pry the cylinder (1) upwards. - Remove the decompression valve, b 6.9 - Inspect the piston and piston rings and replace if necessary, b 6.7, b 6.8 4903RA071 TG 4903RA072 TG 4903RA074 TG 32 MS 311, MS 391...
...the screws (arrows). : Pull the crankshaft (1) out of the cylinder. - Remove the shroud, b 6.4 1 - Pull off the boot and unscrew the spark plug, - Remove the filter base, b 12.3 - Remove the cylinder with piston out of the bearing seats (arrows). : Carefully pull... Cylinder / Crankshaft 1 - Remove the manifold, b 12.9 - Remove the muffler, b 6.1 : Use the lug (arrow) to pry the cylinder (1) upwards. - Remove the decompression valve, b 6.9 - Inspect the piston and piston rings and replace if necessary, b 6.7, b 6.8 4903RA071 TG 4903RA072 TG 4903RA074 TG 32 MS 311, MS 391...
User Manual
Page 35
... of ring breakage. Inspect and clean the sealing face on the right. - Hold the crankshaft (1) steady. : Fit the cylinder (2) with damaged sealing faces. : Apply sealant to the groove in the engine housing. 34 MS 311, MS 391 Always replace components with crankshaft (1) in the sealing face, b 14 4903RA075 TG 4903RA090 TG 4903RA079 TG - Viewed...
... of ring breakage. Inspect and clean the sealing face on the right. - Hold the crankshaft (1) steady. : Fit the cylinder (2) with damaged sealing faces. : Apply sealant to the groove in the engine housing. 34 MS 311, MS 391 Always replace components with crankshaft (1) in the sealing face, b 14 4903RA075 TG 4903RA090 TG 4903RA079 TG - Viewed...
User Manual
Page 36
... crankshaft stub. 4903RA082 TG When fitting a replacement crankshaft, always install new ball bearings and oil seals. Install the piston, b 6.7 - Remove the cylinder, b 6.5 1 - Heat the bearing inner race to about 150°C (300°F). : Push the ball bearing onto the tapered crankshaft stub ... must be installed quickly because the crankshaft stubs absorb heat and expand. - Install the crankshaft and oil seals, b 6.5 MS 311, MS 391 35 1 1 4903RA085 TG 4903RA083 TG 4903RA072 TG : Fit the screws (arrows). : Tighten down the screws (arrows) in the reverse sequence. 2...
... crankshaft stub. 4903RA082 TG When fitting a replacement crankshaft, always install new ball bearings and oil seals. Install the piston, b 6.7 - Remove the cylinder, b 6.5 1 - Heat the bearing inner race to about 150°C (300°F). : Push the ball bearing onto the tapered crankshaft stub ... must be installed quickly because the crankshaft stubs absorb heat and expand. - Install the crankshaft and oil seals, b 6.5 MS 311, MS 391 35 1 1 4903RA085 TG 4903RA083 TG 4903RA072 TG : Fit the screws (arrows). : Tighten down the screws (arrows) in the reverse sequence. 2...
User Manual
Page 37
...) points to remove the hookless snap ring from the installing tool (2) 5910 890 2212. 36 MS 311, MS 391 Lubricate the piston pin (2) with oil and push it and replace if necessary, 1 b 14 533RA126 TG Installing 1 - Remove the cylinder, b 6.5 The snap ring at the recess (arrow) to the rear and the long crankshaft stub...
...) points to remove the hookless snap ring from the installing tool (2) 5910 890 2212. 36 MS 311, MS 391 Lubricate the piston pin (2) with oil and push it and replace if necessary, 1 b 14 533RA126 TG Installing 1 - Remove the cylinder, b 6.5 The snap ring at the recess (arrow) to the rear and the long crankshaft stub...
User Manual
Page 39
...completely or shows signs of the piston rings (arrows). - Check the oil seals and ball bearings and replace if necessary, b 6.5 - Install the cylinder, b 6.5 : Install the new piston rings in the reverse sequence. : Check the sealing cone (arrow) on the decompression valve for damage. -...from the piston. : Position the piston rings so that the radii face upward (arrows). 1 - Reassemble all other parts in the reverse sequence. 38 MS 311, MS 391 Remove the piston, b 6.7 - Inspect the piston rings and replace if necessary, b 6.8 - Remove the shroud, b 6.4 : Unscrew the ...
...completely or shows signs of the piston rings (arrows). - Check the oil seals and ball bearings and replace if necessary, b 6.5 - Install the cylinder, b 6.5 : Install the new piston rings in the reverse sequence. : Check the sealing cone (arrow) on the decompression valve for damage. -...from the piston. : Position the piston rings so that the radii face upward (arrows). 1 - Reassemble all other parts in the reverse sequence. 38 MS 311, MS 391 Remove the piston, b 6.7 - Inspect the piston rings and replace if necessary, b 6.8 - Remove the shroud, b 6.4 : Unscrew the ...
User Manual
Page 42
...timing. : Connect the spark plug boot to the edge of the housing and its open side (arrow) facing the cylinder. 1 2 3 - risk of the troubleshooting chart, b 7.8 MS 311, MS 391 41 If a spark is visible, the ignition system is visible in the window (2), check the ignition system with ...terminal (1) and push the tester's output terminal (3) onto the spark plug. distance 'a' about 2 mm, see window (3). Reassemble all other parts in the cylinder and tighten it down firmly. 23 4 - Using the ZAT 4 ignition tester 1 5910 850 4503 Using the ZAT 3 ignition tester 5910 850 4520 2...
...timing. : Connect the spark plug boot to the edge of the housing and its open side (arrow) facing the cylinder. 1 2 3 - risk of the troubleshooting chart, b 7.8 MS 311, MS 391 41 If a spark is visible, the ignition system is visible in the window (2), check the ignition system with ...terminal (1) and push the tester's output terminal (3) onto the spark plug. distance 'a' about 2 mm, see window (3). Reassemble all other parts in the cylinder and tighten it down firmly. 23 4 - Using the ZAT 4 ignition tester 1 5910 850 4503 Using the ZAT 3 ignition tester 5910 850 4520 2...