Instruction Manual
Page 2
...MS 231, MS 231 C, MS 251, MS 251 C q © ANDREAS STIHL AG & Co. Models with QuickStop Super 24 5.4.1 Adjusting the brake cable 26 5.4.2 Brake cable Removing and Installing 27 5.5 Chain Tensioner 29 5.5.1 Quick Chain Tensioner 30 5.5.2 Chain Catcher 30 5.6 Bar Mounting Stud 31 6. KG, 2010 1 Chain...Lockout Lever 72 10.3 Throttle Trigger/ Lockout Lever - Troubleshooting 8 3.1 Clutch 8 3.2 Chain Drive, Chain Brake, Chain Tensioner 9 3.3 Chain Lubrication 11 3.4 Rewind Starter 12 3.5 Ignition System 14 3.6 Carburetor 15 3.7 Engine 18 4. Introduction and ...
...MS 231, MS 231 C, MS 251, MS 251 C q © ANDREAS STIHL AG & Co. Models with QuickStop Super 24 5.4.1 Adjusting the brake cable 26 5.4.2 Brake cable Removing and Installing 27 5.5 Chain Tensioner 29 5.5.1 Quick Chain Tensioner 30 5.5.2 Chain Catcher 30 5.6 Bar Mounting Stud 31 6. KG, 2010 1 Chain...Lockout Lever 72 10.3 Throttle Trigger/ Lockout Lever - Troubleshooting 8 3.1 Clutch 8 3.2 Chain Drive, Chain Brake, Chain Tensioner 9 3.3 Chain Lubrication 11 3.4 Rewind Starter 12 3.5 Ignition System 14 3.6 Carburetor 15 3.7 Engine 18 4. Introduction and ...
Instruction Manual
Page 5
...voltages which components are not approved and may result in damage to overheating. 4 MS 231, MS 231 C, MS 251, MS 251 C Check disassembled parts for operations in which occur can be explosive in line with...fuel and can cause serious or fatal accidents. Preparations for servicing Remove the chain sprocket cover, saw chain and guide bar before re-installing - They can be maintained when tightening...wear or damage before carrying out repairs or mounting the machine to ensure the tightness of STIHL press fluid, b 14. Gasoline is otherwise a risk of injury from the fanwheel and ...
...voltages which components are not approved and may result in damage to overheating. 4 MS 231, MS 231 C, MS 251, MS 251 C Check disassembled parts for operations in which occur can be explosive in line with...fuel and can cause serious or fatal accidents. Preparations for servicing Remove the chain sprocket cover, saw chain and guide bar before re-installing - They can be maintained when tightening...wear or damage before carrying out repairs or mounting the machine to ensure the tightness of STIHL press fluid, b 14. Gasoline is otherwise a risk of injury from the fanwheel and ...
Instruction Manual
Page 6
...: Crankcase leakage test at gauge pressure: under vacuum: 2.2 Fuel System 2.3 Ignition System 2.4 Chain Lubrication MS 231 40.6 cm3 41.5 mm 30.0 mm 2.0 kW (2.7 bhp) at 9,500 rpm 13,000 rpm 2,800 rpm Centrifugal clutch without linings 3,500 rpm 0.5 bar 0.5 bar MS 251 45.6 cm3 44.0 mm 30.0 mm 2.2 kW (3.0 bhp) at 9,500 rpm 13... (resistor type): Electrode gap: 0.30 (+ 0.05/- 0.10) mm NGK CMR 6 H 0.5 mm Speed-controlled Ematic oil pump Oil delivery rate: 8.0 (+/3.0) cm3/min at 10,000 rpm MS 231, MS 231 C, MS 251, MS 251 C 5
...: Crankcase leakage test at gauge pressure: under vacuum: 2.2 Fuel System 2.3 Ignition System 2.4 Chain Lubrication MS 231 40.6 cm3 41.5 mm 30.0 mm 2.0 kW (2.7 bhp) at 9,500 rpm 13,000 rpm 2,800 rpm Centrifugal clutch without linings 3,500 rpm 0.5 bar 0.5 bar MS 251 45.6 cm3 44.0 mm 30.0 mm 2.2 kW (3.0 bhp) at 9,500 rpm 13... (resistor type): Electrode gap: 0.30 (+ 0.05/- 0.10) mm NGK CMR 6 H 0.5 mm Speed-controlled Ematic oil pump Oil delivery rate: 8.0 (+/3.0) cm3/min at 10,000 rpm MS 231, MS 231 C, MS 251, MS 251 C 5
Instruction Manual
Page 7
... 5x16 Muffler / cylinder 10.0 M 8x1 Flywheel / crankshaft 28.0 P 4x10 Retainer 1.0 Q B 2), 3) 2) 1), 3) 1), 3) 1), 3) 2), 3) 4) 6 MS 231, MS 231 C, MS 251, MS 251 C Fastener Thread size For component Torque Nm Remarks Screw Screw Screw Screw Screw Collar screw Collar screw Collar screw Screw Nut Screw Screw Screw... Screw Screw Screw Screw Screw Screw Carrier Screw Screw Screw Nut Screw P 4x12 Chain...
... 5x16 Muffler / cylinder 10.0 M 8x1 Flywheel / crankshaft 28.0 P 4x10 Retainer 1.0 Q B 2), 3) 2) 1), 3) 1), 3) 1), 3) 2), 3) 4) 6 MS 231, MS 231 C, MS 251, MS 251 C Fastener Thread size For component Torque Nm Remarks Screw Screw Screw Screw Screw Collar screw Collar screw Collar screw Screw Nut Screw Screw Screw... Screw Screw Screw Screw Screw Screw Carrier Screw Screw Screw Nut Screw P 4x12 Chain...
Instruction Manual
Page 8
...encapsulated screws with binding head 2) Micro-encapsulated screws 3) Waxed screws 4) Degrease crankshaft/flywheel and mount oil-free Q) QuickStop Super B) Quick chain adjuster Use the following procedure when refitting a DG or P screw in an existing thread: Place the screw in the existing thread and...assembly. This procedure ensures that the screw engages properly in the hole and rotate it counterclockwise until it drops down slightly. MS 231, MS 231 C, MS 251, MS 251 C 7 Tighten the screw clockwise to the specified torque. Do not mix up screws with and without binding heads. Power ...
...encapsulated screws with binding head 2) Micro-encapsulated screws 3) Waxed screws 4) Degrease crankshaft/flywheel and mount oil-free Q) QuickStop Super B) Quick chain adjuster Use the following procedure when refitting a DG or P screw in an existing thread: Place the screw in the existing thread and...assembly. This procedure ensures that the screw engages properly in the hole and rotate it counterclockwise until it drops down slightly. MS 231, MS 231 C, MS 251, MS 251 C 7 Tighten the screw clockwise to the specified torque. Do not mix up screws with and without binding heads. Power ...
Instruction Manual
Page 9
... under full load Cause Clutch shoes badly worn Clutch drum badly worn Remedy Install new clutch Install new clutch drum Saw chain rotates at idle speed Engine idle speed too high Clutch springs stretched Clutch springs broken Readjust idle speed screw LA Replace the clutch springs or ... Clutch shoe retainer broken Clutch shoes and carrier worn Replace all clutch springs Fit new needle cage Install new retainer or clutch Install new clutch 8 MS 231, MS 231 C, MS 251, MS 251 C 3.
... under full load Cause Clutch shoes badly worn Clutch drum badly worn Remedy Install new clutch Install new clutch drum Saw chain rotates at idle speed Engine idle speed too high Clutch springs stretched Clutch springs broken Readjust idle speed screw LA Replace the clutch springs or ... Clutch shoe retainer broken Clutch shoes and carrier worn Replace all clutch springs Fit new needle cage Install new retainer or clutch Install new clutch 8 MS 231, MS 231 C, MS 251, MS 251 C 3.
Instruction Manual
Page 10
...drum badly worn Brake band blocked Install new clutch Install new clutch drum Check freedom of movement and operation of brake band Saw chain rotates at idle speed Engine idle speed too high Clutch springs stretched Clutch springs broken Readjust idle speed screw LA Replace the clutch... springs or install new clutch Replace the clutch springs Saw chain does not stop immediately when brake is activated Brake spring stretched or broken Fit new brake spring Brake band stretched or worn Clutch drum worn Fit new brake band Install new clutch drum MS 231, MS 231 C, MS 251, MS 251 C 9
...drum badly worn Brake band blocked Install new clutch Install new clutch drum Check freedom of movement and operation of brake band Saw chain rotates at idle speed Engine idle speed too high Clutch springs stretched Clutch springs broken Readjust idle speed screw LA Replace the clutch... springs or install new clutch Replace the clutch springs Saw chain does not stop immediately when brake is activated Brake spring stretched or broken Fit new brake spring Brake band stretched or worn Clutch drum worn Fit new brake band Install new clutch drum MS 231, MS 231 C, MS 251, MS 251 C 9
Instruction Manual
Page 12
... Install new engine housing Oil pump delivers insufficient oil Oil pump damaged or worn Worm driver is loose Install new oil pump Install new worm MS 231, MS 231 C, MS 251, MS 251 C 11 3.3 Chain Lubrication In the event of faults before disassembling the oil pump. rectify other sources of trouble with the...
... Install new engine housing Oil pump delivers insufficient oil Oil pump damaged or worn Worm driver is loose Install new oil pump Install new worm MS 231, MS 231 C, MS 251, MS 251 C 11 3.3 Chain Lubrication In the event of faults before disassembling the oil pump. rectify other sources of trouble with the...
Instruction Manual
Page 17
... - throttle shutter completely closed Tank vent faulty Clean the carburetor Reset low speed screw (L) correctly Reset idle speed screw (LA) correctly Replace tank vent Saw chain rotates at idle speed Leak on fuel hose from tank to carburetor Seal connections or install new fuel hose Engine idle speed too high Readjust... screw LA (counterclockwise) Clutch springs stretched or fatigued Replace the clutch springs or install new clutch Clutch spring hooks broken Replace the clutch springs 16 MS 231, MS 231 C, MS 251, MS 251 C
... - throttle shutter completely closed Tank vent faulty Clean the carburetor Reset low speed screw (L) correctly Reset idle speed screw (LA) correctly Replace tank vent Saw chain rotates at idle speed Leak on fuel hose from tank to carburetor Seal connections or install new fuel hose Engine idle speed too high Readjust... screw LA (counterclockwise) Clutch springs stretched or fatigued Replace the clutch springs or install new clutch Clutch spring hooks broken Replace the clutch springs 16 MS 231, MS 231 C, MS 251, MS 251 C
Instruction Manual
Page 21
... With the coasting brake disengaged, open the throttle wide for a brief 1 TOP period (max. 3 seconds) - 5. If the chain brake does not operate properly, refer to the eye. Its efficiency is depressed. Contamination (with QuickStop Super - Remove the brake band without... . : Take out the screws (1). : Remove the cover (2). 219RA049 TG Machines with chain oil, chips, fine particles of abrasion, etc.) and smoothing of the friction surfaces of the brake band and clutch drum impair the coefficient of the machine. 20 MS 231, MS 231 C, MS 251, MS 251 C
... With the coasting brake disengaged, open the throttle wide for a brief 1 TOP period (max. 3 seconds) - 5. If the chain brake does not operate properly, refer to the eye. Its efficiency is depressed. Contamination (with QuickStop Super - Remove the brake band without... . : Take out the screws (1). : Remove the cover (2). 219RA049 TG Machines with chain oil, chips, fine particles of abrasion, etc.) and smoothing of the friction surfaces of the brake band and clutch drum impair the coefficient of the machine. 20 MS 231, MS 231 C, MS 251, MS 251 C
Instruction Manual
Page 22
...assembly tool 1117 890 0900 to the brake lever (2) and then swing it down the screws (2) firmly. 2310RA014 TG 1 TOP - Engage the chain brake. 1 2 TOP 2 TOP 1 2310RA011 TG : Place the cover (1) in the slots (arrows) first. - Remove the brake spring... Engage the chain brake. Reassemble all other checks, b 5.1 - Install the clutch drum, b 4.1 2 OP 1 - Remove the fan housing, b 8.2 1 - Disengage the chain brake : Hold the brake band (1) sideways, attach it to disconnect the brake spring (1) from the brake lever. 2310RA015 TG MS 231, MS 231 C, MS 251, MS 251 C 21 ...
...assembly tool 1117 890 0900 to the brake lever (2) and then swing it down the screws (2) firmly. 2310RA014 TG 1 TOP - Engage the chain brake. 1 2 TOP 2 TOP 1 2310RA011 TG : Place the cover (1) in the slots (arrows) first. - Remove the brake spring... Engage the chain brake. Reassemble all other checks, b 5.1 - Install the clutch drum, b 4.1 2 OP 1 - Remove the fan housing, b 8.2 1 - Disengage the chain brake : Hold the brake band (1) sideways, attach it to disconnect the brake spring (1) from the brake lever. 2310RA015 TG MS 231, MS 231 C, MS 251, MS 251 C 21 ...
Instruction Manual
Page 25
... and brake lever. 2310RA033 TG 1 : Take the brake lever (2) out of the flat spring (1) into its seat (arrow) as far as stop. 2310RA020 TG 24 MS 231, MS 231 C, MS 251, MS 251 C 2310RA035 TG 5.4 Brake Lever on the hand guard and replace the hand 1 guard if necessary. Troubleshooting, b 3.2 - Engage the...
... and brake lever. 2310RA033 TG 1 : Take the brake lever (2) out of the flat spring (1) into its seat (arrow) as far as stop. 2310RA020 TG 24 MS 231, MS 231 C, MS 251, MS 251 C 2310RA035 TG 5.4 Brake Lever on the hand guard and replace the hand 1 guard if necessary. Troubleshooting, b 3.2 - Engage the...
Instruction Manual
Page 27
.... : Attach the spring (1) to the anchor pin (2). : Use the assembly tool 1117 890 0900 to the brake lever (arrow). 26 MS 231, MS 231 C, MS 251, MS 251 C Troubleshooting, b 3.2 TOP 2310RA043 TG : Attach the spring (1) to disconnect the brake spring (1) from the anchor pin (arrow). -...even though the brake band is not the case, replace the brake spring. - Troubleshooting, b 3.2 - Adjust the brake cable, b 5.4.1 - Remove the chain brake cover, b 5.2 The brake cable must rotate freely. - Reassemble all other parts in hand guard, b 14 - A certain amount of the coasting ...
.... : Attach the spring (1) to the anchor pin (2). : Use the assembly tool 1117 890 0900 to the brake lever (arrow). 26 MS 231, MS 231 C, MS 251, MS 251 C Troubleshooting, b 3.2 TOP 2310RA043 TG : Attach the spring (1) to disconnect the brake spring (1) from the anchor pin (arrow). -...even though the brake band is not the case, replace the brake spring. - Troubleshooting, b 3.2 - Adjust the brake cable, b 5.4.1 - Remove the chain brake cover, b 5.2 The brake cable must rotate freely. - Reassemble all other parts in hand guard, b 14 - A certain amount of the coasting ...
Instruction Manual
Page 30
... the brake cable will vary. - Reassemble all other parts in the guide (arrow). - Install the throttle trigger, b 10.3 MS 231, MS 231 C, MS 251, MS 251 C 29 Check operation and adjust the brake cable, b 5.4.1 2310RA060 TG 2710RA079 TG 5.5 Chain Tensioner 2310RA066 TG : Attach the brake cable (1) to the bore (arrow) in the brake lever (2). 2 1 : Slide the brake...
... the brake cable will vary. - Reassemble all other parts in the guide (arrow). - Install the throttle trigger, b 10.3 MS 231, MS 231 C, MS 251, MS 251 C 29 Check operation and adjust the brake cable, b 5.4.1 2310RA060 TG 2710RA079 TG 5.5 Chain Tensioner 2310RA066 TG : Attach the brake cable (1) to the bore (arrow) in the brake lever (2). 2 1 : Slide the brake...
Instruction Manual
Page 31
...MS 231 C, MS 251, MS 251 C Lubricate thread and gears with the contour of the recess (arrows). : Insert and tighten down until it out of the sprocket cover (1). - Reassemble in the reverse sequence. - If the chain catcher is damaged or worn, install a replacement chain catcher. 2310RA045 TG 5.5.1 Quick Chain Tensioner The quick chain...carefully pry it snaps into position. 1 2 1 The chain catcher (arrow) is installed in the reverse sequence. 1 : Position the replacement chain catcher (1) so that it lines up with STIHL multipurpose grease, b 14 - Reassemble in the reverse ...
...MS 231 C, MS 251, MS 251 C Lubricate thread and gears with the contour of the recess (arrows). : Insert and tighten down until it out of the sprocket cover (1). - Reassemble in the reverse sequence. - If the chain catcher is damaged or worn, install a replacement chain catcher. 2310RA045 TG 5.5.1 Quick Chain Tensioner The quick chain...carefully pry it snaps into position. 1 2 1 The chain catcher (arrow) is installed in the reverse sequence. 1 : Position the replacement chain catcher (1) so that it lines up with STIHL multipurpose grease, b 14 - Reassemble in the reverse ...
Instruction Manual
Page 32
... all other parts in the engine housing is no longer guaranteed. Fit the collar stud by hand so that it down firmly, b 14 - Remove the chain sprocket cover. 2 1 Repair solution If the thread in the reverse sequence. In such a case use the collar stud in the reverse sequence. : Coat the thread..., b 2.5. 1 2310RA046 TG 2310RA047 TG : Push stud puller 5910 893 0501 (1) over the collar stud (2) as far as it will go and unscrew the stud counterclockwise. - MS 231, MS 231 C, MS 251, MS 251 C 31
... all other parts in the engine housing is no longer guaranteed. Fit the collar stud by hand so that it down firmly, b 14 - Remove the chain sprocket cover. 2 1 Repair solution If the thread in the reverse sequence. In such a case use the collar stud in the reverse sequence. : Coat the thread..., b 2.5. 1 2310RA046 TG 2310RA047 TG : Push stud puller 5910 893 0501 (1) over the collar stud (2) as far as it will go and unscrew the stud counterclockwise. - MS 231, MS 231 C, MS 251, MS 251 C 31
Instruction Manual
Page 79
...: Use hook (2) 5910 893 8800 to re-position it and replace if necessary. - Pull off the pickup body (1), check it . - 11. Chain Lubrication 11.1 Pickup Body 11.2 Oil Suction Hose Impurities gradually clog the fine pores of the filter with the pickup body. - Remove the brake band... hose and pickup body and replace if 2 necessary. - Push the oil suction hose (1), pickup body first, through the housing bore (arrow). 78 MS 231, MS 231 C, MS 251, MS 251 C Remove the clutch, b 4 - Open the oil tank cap and drain the oil tank. 1 - Push home the oil suction hose (1) ...
...: Use hook (2) 5910 893 8800 to re-position it and replace if necessary. - Pull off the pickup body (1), check it . - 11. Chain Lubrication 11.1 Pickup Body 11.2 Oil Suction Hose Impurities gradually clog the fine pores of the filter with the pickup body. - Remove the brake band... hose and pickup body and replace if 2 necessary. - Push the oil suction hose (1), pickup body first, through the housing bore (arrow). 78 MS 231, MS 231 C, MS 251, MS 251 C Remove the clutch, b 4 - Open the oil tank cap and drain the oil tank. 1 - Push home the oil suction hose (1) ...
Instruction Manual
Page 96
...speed screw (L) has to make the mixture any leaner - 12.7 Adjusting the Carburetor 12.7.1 Basic Setting The basic setting is the basic setting. - Check chain tension and adjust if necessary. - Check the air filter and clean or replace if necessary, b 12.1 1 2 : Starting with a tachometer. this is...screw L (2) against its seat, open ). Use the idle speed screw (LA) to set the engine's maximum speed to 3,300 rpm. 4. MS 231, MS 231 C, MS 251, MS 251 C 95 push the screwdriver through the pre-installed limiter cap on the screwdriver 5910 890 2306 to 2,800 rpm. 5. As soon as a ...
...speed screw (L) has to make the mixture any leaner - 12.7 Adjusting the Carburetor 12.7.1 Basic Setting The basic setting is the basic setting. - Check chain tension and adjust if necessary. - Check the air filter and clean or replace if necessary, b 12.1 1 2 : Starting with a tachometer. this is...screw L (2) against its seat, open ). Use the idle speed screw (LA) to set the engine's maximum speed to 3,300 rpm. 4. MS 231, MS 231 C, MS 251, MS 251 C 95 push the screwdriver through the pre-installed limiter cap on the screwdriver 5910 890 2306 to 2,800 rpm. 5. As soon as a ...
Instruction Manual
Page 97
...idle speed screw (LA) counterclockwise until the chain stops running , then turn it back 1 full turn . - It is usually necessary to the low speed screw (L). The setting of lubrication and overheating. 96 MS 231, MS 231 C, MS 251, MS 251 C Inspect the spark arresting screen (if ... the engine. Troubleshooting, b 3.6 - Turn the high speed screw (H) slowly counterclockwise as far as stop . Carry out standard setting. - Check chain tension and adjust if necessary. - Check running behavior. Warm up the engine. - Warm up the engine. - Turn the high speed screw (H)...
...idle speed screw (LA) counterclockwise until the chain stops running , then turn it back 1 full turn . - It is usually necessary to the low speed screw (L). The setting of lubrication and overheating. 96 MS 231, MS 231 C, MS 251, MS 251 C Inspect the spark arresting screen (if ... the engine. Troubleshooting, b 3.6 - Turn the high speed screw (H) slowly counterclockwise as far as stop . Carry out standard setting. - Check chain tension and adjust if necessary. - Check running behavior. Warm up the engine. - Warm up the engine. - Turn the high speed screw (H)...