Product Instruction Manual
Page 3
... all of the Guide Bar 35 Air Filter System 36 Cleaning the Air Filter 36 Engine Management 37 Adjusting the Carburetor 37 Spark Arresting Screen in Muffler 38 Spark Plug 39 Replacing the Starter Rope and Rewind Spring 40 Storing the Machine 42 Checking and Replacing the Chain Sprocket 43 Maintaining and Sharpening the Saw Chain 44 Maintenance and Care 47 { Main Parts Specifications Special Accessories Ordering Spare Parts Maintenance and Repairs STIHL Incorporated Federal Emission Control Warranty Statement Trademarks MS 311, MS 391 English 49...
... all of the Guide Bar 35 Air Filter System 36 Cleaning the Air Filter 36 Engine Management 37 Adjusting the Carburetor 37 Spark Arresting Screen in Muffler 38 Spark Plug 39 Replacing the Starter Rope and Rewind Spring 40 Storing the Machine 42 Checking and Replacing the Chain Sprocket 43 Maintaining and Sharpening the Saw Chain 44 Maintenance and Care 47 { Main Parts Specifications Special Accessories Ordering Spare Parts Maintenance and Repairs STIHL Incorporated Federal Emission Control Warranty Statement Trademarks MS 311, MS 391 English 49...
Product Instruction Manual
Page 7
... your power tool with the saw chain contact, never carry or transport your instruction manual). It may escape from saw chain moving. Fuel Your STIHL power tool uses an oilgasoline mixture for fuel (see the chapter on your body and the cutting attachment behind you. Fueling Instructions Warning! Warning! If this machine if it will go (approx. MS 311, MS 391 5 Do not continue operating this happens, change your power tool in a manner that combustible fuel vapor...
... your power tool with the saw chain contact, never carry or transport your instruction manual). It may escape from saw chain moving. Fuel Your STIHL power tool uses an oilgasoline mixture for fuel (see the chapter on your body and the cutting attachment behind you. Fueling Instructions Warning! Warning! If this machine if it will go (approx. MS 311, MS 391 5 Do not continue operating this happens, change your power tool in a manner that combustible fuel vapor...
Product Instruction Manual
Page 8
..., oil, fuel mix, grease or resin in your power tool. Before replacing any bar and chain, see the appropriate section of the chain is shut off the engine and then tighten. Warning! Always make sure the hexagonal nut(s) for proper condition and operation before starting, particularly the throttle trigger, throttle trigger lockout, stop switch and cutting tool. Check chain tension once more after tensioning the chain in the filler opening, the cap is damaged, improperly adjusted...
..., oil, fuel mix, grease or resin in your power tool. Before replacing any bar and chain, see the appropriate section of the chain is shut off the engine and then tighten. Warning! Always make sure the hexagonal nut(s) for proper condition and operation before starting, particularly the throttle trigger, throttle trigger lockout, stop switch and cutting tool. Check chain tension once more after tensioning the chain in the filler opening, the cap is damaged, improperly adjusted...
Product Instruction Manual
Page 9
... the engine is engaged (see section on the handles while you pull the starter grip, do not use your unit with the starting throttle lock engaged will disengage the starting . Make sure the chain brake is running cutting tool, do not wrap the starter rope around the handles. For saws with a rear handle level with your instruction manual) and place the chain saw . Keep your right foot into the rear handle and press down . Warning! MS 311, MS...
... the engine is engaged (see section on the handles while you pull the starter grip, do not use your unit with the starting throttle lock engaged will disengage the starting . Make sure the chain brake is running cutting tool, do not wrap the starter rope around the handles. For saws with a rear handle level with your instruction manual) and place the chain saw . Keep your right foot into the rear handle and press down . Warning! MS 311, MS...
Product Instruction Manual
Page 12
.... A "sponginess" in loss of control of injury, e.g., from any questions as to time, the catcher may also permanently damage the engine. Warning! Warning! Antivibration elements should be replaced, consult your power tool using the starting throttle lock, as pine needles, branches or leaves. You may be replaced in the cut or the chain brake is released (flywheel effect). Operating instructions Warning! From time to whether the antivibration elements...
.... A "sponginess" in loss of control of injury, e.g., from any questions as to time, the catcher may also permanently damage the engine. Warning! Warning! Antivibration elements should be replaced, consult your power tool using the starting throttle lock, as pine needles, branches or leaves. You may be replaced in the cut or the chain brake is released (flywheel effect). Operating instructions Warning! From time to whether the antivibration elements...
Product Instruction Manual
Page 15
... or other parts of your instruction manual entitled "Chain Brake" and the section "Maintenance, Repair and Storing" at all. See the chapter of the hand guard on newer STIHL chain saws can cause excessive heat, leading to reduce the risk of ANSI B 175.1-2000 MS 311, MS 391 13 The chain brake on a saw above at "Important Adjustments"). These devices are designed to severe damage of the motor housing, clutch and...
... or other parts of your instruction manual entitled "Chain Brake" and the section "Maintenance, Repair and Storing" at all. See the chapter of the hand guard on newer STIHL chain saws can cause excessive heat, leading to reduce the risk of ANSI B 175.1-2000 MS 311, MS 391 13 The chain brake on a saw above at "Important Adjustments"). These devices are designed to severe damage of the motor housing, clutch and...
Product Instruction Manual
Page 24
... the chain brake and can spot a dull chain when easy-to-cut and burn marks appear on the drum. Tighten all nuts, bolts and screws except the carburetor adjustment screws after each time it and the ignition lead are always clean and in the instruction manual). 22 MS 311, MS 391 every three months, Moderate usage - Remember that could ignite combustible fumes and cause a fire. replace worn sprockets or chains. In...
... the chain brake and can spot a dull chain when easy-to-cut and burn marks appear on the drum. Tighten all nuts, bolts and screws except the carburetor adjustment screws after each time it and the ignition lead are always clean and in the instruction manual). 22 MS 311, MS 391 every three months, Moderate usage - Remember that could ignite combustible fumes and cause a fire. replace worn sprockets or chains. In...
Product Instruction Manual
Page 32
... switched off - ignition is used, the slide must be in the winter position. the Master Control lever returns to the operating position when the throttle trigger is for starting the warm engine - engine off Operating position F - this position is running or can start Warm start l - In case of the Master Control lever STOP 0 Stop 0 - after starting the cold engine 30 MS 311, MS 391 engine is for starting , bring the engine up to operating temperature at increased idle speed (disengage chain brake!) Cover plate 2 2 1 N Insert cover...
... switched off - ignition is used, the slide must be in the winter position. the Master Control lever returns to the operating position when the throttle trigger is for starting the warm engine - engine off Operating position F - this position is running or can start Warm start l - In case of the Master Control lever STOP 0 Stop 0 - after starting the cold engine 30 MS 311, MS 391 engine is for starting , bring the engine up to operating temperature at increased idle speed (disengage chain brake!) Cover plate 2 2 1 N Insert cover...
Product Instruction Manual
Page 35
... temperatures N let the engine warm up briefly with the throttle slightly open N if necessary, configure for use. see "Spark plug" N Set the Master Control lever to clear the combustion chamber N Replace the spark plug - Once the engine is ready for winter operation, see "Spark plug" N Dry spark plug N Crank the engine several times with the chain brake on (saw is running STOP 1 0 2 N Press the throttle trigger interlock and blip the throttle trigger (2); the chain saw chain is cold MS 311, MS 391 33
... temperatures N let the engine warm up briefly with the throttle slightly open N if necessary, configure for use. see "Spark plug" N Set the Master Control lever to clear the combustion chamber N Replace the spark plug - Once the engine is ready for winter operation, see "Spark plug" N Dry spark plug N Crank the engine several times with the chain brake on (saw is running STOP 1 0 2 N Press the throttle trigger interlock and blip the throttle trigger (2); the chain saw chain is cold MS 311, MS 391 33
Product Instruction Manual
Page 41
N Pull off the spark plug boot N Unscrew spark plug Remove the spark plug N Move the Master Control lever to start or runs poorly at part throttle etc.) affect the condition of the spark plug. the saw chain is blocked 1 4903BA007 KN English N Remove spark plug - see "Starting / Stopping the Engine". MS 311, MS 391 39 Fit a new spark plug after approx. 100 operating hours or earlier if the electrodes are badly eroded. Wrong fuel mix (too much engine oil in the gasoline), a dirty air filter and unfavorable...
N Pull off the spark plug boot N Unscrew spark plug Remove the spark plug N Move the Master Control lever to start or runs poorly at part throttle etc.) affect the condition of the spark plug. the saw chain is blocked 1 4903BA007 KN English N Remove spark plug - see "Starting / Stopping the Engine". MS 311, MS 391 39 Fit a new spark plug after approx. 100 operating hours or earlier if the electrodes are badly eroded. Wrong fuel mix (too much engine oil in the gasoline), a dirty air filter and unfavorable...
Product Instruction Manual
Page 52
... wheel that drives the saw chain. 8 Chain Sprocket Cover Covers the clutch and chain sprocket. 9 Chain Catcher Helps to operator's right hand. when activated. 6 Chain Brake A device to stop the rotation of vibrations created by the engine and cutting attachment to make engine starting throttle, run and stop switch position. 21 Throttle Trigger Controls the speed of the engine. 22 Throttle Trigger Lockout Must be depressed before the throttle trigger can be activated. 23 Rear Handle The support handle for the shroud. 2 Carburetor Adjusting Screws For tuning the carburetor. 3 Spark Plug...
... wheel that drives the saw chain. 8 Chain Sprocket Cover Covers the clutch and chain sprocket. 9 Chain Catcher Helps to operator's right hand. when activated. 6 Chain Brake A device to stop the rotation of vibrations created by the engine and cutting attachment to make engine starting throttle, run and stop switch position. 21 Throttle Trigger Controls the speed of the engine. 22 Throttle Trigger Lockout Must be depressed before the throttle trigger can be activated. 23 Rear Handle The support handle for the shroud. 2 Carburetor Adjusting Screws For tuning the carburetor. 3 Spark Plug...
Product Instruction Manual
Page 55
... type engine. This will repair your small off -road equipment engine. STIHL Incorporated Federal Emission Control Warranty Statement Your Warranty Rights and Obligations The U.S. Model Serial number Guide bar part number Chain part number See "Specifications" in this manual. Where a warrantable condition exists, STIHL Incorporated will make reordering simpler. EPA standards for the recommended reduced kickback cutting attachments. new 1997 and later model year small off-road equipment engines must be designed, built and equipped, at the time...
... type engine. This will repair your small off -road equipment engine. STIHL Incorporated Federal Emission Control Warranty Statement Your Warranty Rights and Obligations The U.S. Model Serial number Guide bar part number Chain part number See "Specifications" in this manual. Where a warrantable condition exists, STIHL Incorporated will make reordering simpler. EPA standards for the recommended reduced kickback cutting attachments. new 1997 and later model year small off-road equipment engines must be designed, built and equipped, at the time...
Product Instruction Manual
Page 56
..., however, that STIHL Incorporated may be used for any emission-related part on your failure to the owner. STIHL Incorporated is defective. Any replacement part or service that a warranted part is defective. You are responsible for 54 MS 311, MS 391 However, if you can write to the first scheduled replacement point for the performance of the required maintenance listed in non-warranty maintenance or repairs, and shall...
..., however, that STIHL Incorporated may be used for any emission-related part on your failure to the owner. STIHL Incorporated is defective. Any replacement part or service that a warranted part is defective. You are responsible for 54 MS 311, MS 391 However, if you can write to the first scheduled replacement point for the performance of the required maintenance listed in non-warranty maintenance or repairs, and shall...
User Manual
Page 2
... 59 3. Ignition System 39 10. Control Levers 61 3.1 Clutch 3.2 Chain Drive, Chain Brake, Chain Tensioner 3.3 Chain Lubrication 3.4 Rewind Starter 3.5 Ignition System 3.6 Carburetor 3.7 Engine 4. Rewind Starter 51 5.2 Brake Band 20 5.3 Brake Lever 22 8.1 General 51 5.4 Cam Lever 24 8.2 Fan housing 51 5.5 Pins 25 8.2.1 Segment 51 5.6 Chain Tensioner 25 8.3 Pawls 51 5.7 Bar Mounting Studs 26 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...
... 59 3. Ignition System 39 10. Control Levers 61 3.1 Clutch 3.2 Chain Drive, Chain Brake, Chain Tensioner 3.3 Chain Lubrication 3.4 Rewind Starter 3.5 Ignition System 3.6 Carburetor 3.7 Engine 4. Rewind Starter 51 5.2 Brake Band 20 5.3 Brake Lever 22 8.1 General 51 5.4 Cam Lever 24 8.2 Fan housing 51 5.5 Pins 25 8.2.1 Segment 51 5.6 Chain Tensioner 25 8.3 Pawls 51 5.7 Bar Mounting Studs 26 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...
User Manual
Page 5
.... replace as the safety precautions and warnings in the instruction manual. Do not cut open fuel hoses with the connector, preferably by the STIHL part number, the { logo and the STIHL parts symbol K This symbol may appear alone on small parts. The specifications must be overstretched during removal. hose barb connectors Pull off or push on fuel hoses in line with a knife or similar tool. Improper handling may...
.... replace as the safety precautions and warnings in the instruction manual. Do not cut open fuel hoses with the connector, preferably by the STIHL part number, the { logo and the STIHL parts symbol K This symbol may appear alone on small parts. The specifications must be overstretched during removal. hose barb connectors Pull off or push on fuel hoses in line with a knife or similar tool. Improper handling may...
User Manual
Page 13
... replace if necessary. Clean the spark plug or replace if necessary. Engine housing damaged (cracks) Install new engine housing 12 MS 311, MS 391 If sooting keeps recurring, check air filter Ignition lead loose in ignition lead or short circuit wire. The high voltages which occur can cause serious or fatal accidents. Check ignition lead/ignition module and replace ignition module if necessary. Condition Engine runs roughly, misfires, temporary loss of spark plug. too much oil Use correct mixture of fuel and oil Incorrect air gap between ignition Set air gap...
... replace if necessary. Clean the spark plug or replace if necessary. Engine housing damaged (cracks) Install new engine housing 12 MS 311, MS 391 If sooting keeps recurring, check air filter Ignition lead loose in ignition lead or short circuit wire. The high voltages which occur can cause serious or fatal accidents. Check ignition lead/ignition module and replace ignition module if necessary. Condition Engine runs roughly, misfires, temporary loss of spark plug. too much oil Use correct mixture of fuel and oil Incorrect air gap between ignition Set air gap...
User Manual
Page 17
... MS 311, MS 391 Air inlets in engine housing at idle speed, but operates normally damaged at full throttle Engine housing leaking/ damaged (cracks) Remedy Replace the oil seals Seal or replace the engine housing Engine does not deliver full power Piston rings worn or broken or runs erratically Fit 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 Replace air filter Fuel/impulse hose severely kinked Fit new hoses or position them free...
... MS 311, MS 391 Air inlets in engine housing at idle speed, but operates normally damaged at full throttle Engine housing leaking/ damaged (cracks) Remedy Replace the oil seals Seal or replace the engine housing Engine does not deliver full power Piston rings worn or broken or runs erratically Fit 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 Replace air filter Fuel/impulse hose severely kinked Fit new hoses or position them free...
User Manual
Page 80
... it one full turn counterclockwise - Inspect the spark arresting screen (if fitted) and clean or replace if necessary, b 3.7 or b 6.1 - Warm up the engine. MS 311, MS 391 79 Reassemble in the reverse sequence. - do not push fully home. The carburetor, air filter and grommet are installed, the adjusting screws fitted and the new limiter cap pre-installed. - this is necessary only 1 if the high speed screw (H) or low speed screw (L) has to be...
... it one full turn counterclockwise - Inspect the spark arresting screen (if fitted) and clean or replace if necessary, b 3.7 or b 6.1 - Warm up the engine. MS 311, MS 391 79 Reassemble in the reverse sequence. - do not push fully home. The carburetor, air filter and grommet are installed, the adjusting screws fitted and the new limiter cap pre-installed. - this is necessary only 1 if the high speed screw (H) or low speed screw (L) has to be...
User Manual
Page 81
...: - Set the engine speed to 3,300 rpm. 4. Check the air filter and clean or replace if necessary, b 12.1 3. Use the idle speed screw (LA) to set the engine speed again to 2,800 rpm with a tachometer. Adjust idle speed with the low speed screw ( L). 5. Troubleshooting, b 3.6 - Inspect the spark arresting screen (if fitted) and clean or replace if necessary, b 3.7 or b 6.1 - Adjust specified engine speeds within a tolerance of the high speed screw (H) and the low speed screw (L) and the high speed screw (H) is flush with the high speed screw (H). 80 MS 311, MS 391
...: - Set the engine speed to 3,300 rpm. 4. Check the air filter and clean or replace if necessary, b 12.1 3. Use the idle speed screw (LA) to set the engine speed again to 2,800 rpm with a tachometer. Adjust idle speed with the low speed screw ( L). 5. Troubleshooting, b 3.6 - Inspect the spark arresting screen (if fitted) and clean or replace if necessary, b 3.7 or b 6.1 - Adjust specified engine speeds within a tolerance of the high speed screw (H) and the low speed screw (L) and the high speed screw (H) is flush with the high speed screw (H). 80 MS 311, MS 391
User Manual
Page 89
... Installing rope guide bushing Blocking the crankshaft Removing and installing external circlips Removing and installing spline socket screws with torque wrench Installing tank vent Adjusting air gap between the ignition module and flywheel Removing and installing piston pin Attaching springs Protecting the oil seal Installing oil seal Protecting the oil seal (clutch side) Spark plug 1) Removing flywheel Testing ignition system Testing ignition system 0.5 to 18 Nm 6 to 80 Nm Installing hookless snap rings in piston 88 MS 311, MS 391 Testing engine and carburetor...
... Installing rope guide bushing Blocking the crankshaft Removing and installing external circlips Removing and installing spline socket screws with torque wrench Installing tank vent Adjusting air gap between the ignition module and flywheel Removing and installing piston pin Attaching springs Protecting the oil seal Installing oil seal Protecting the oil seal (clutch side) Spark plug 1) Removing flywheel Testing ignition system Testing ignition system 0.5 to 18 Nm 6 to 80 Nm Installing hookless snap rings in piston 88 MS 311, MS 391 Testing engine and carburetor...
