Instruction Manual
Table Of Contents
- STIHL MS 231, 251
- 1 Guide to Using this Manual
- 2 Safety Precautions
- 3 Reactive Forces
- 4 Working Techniques
- 5 Cutting Attachment
- 6 Mounting the Bar and Chain (side chain tensioner)
- 7 Mounting the Bar and Chain (quick chain tensioner)
- 8 Tensioning the Saw Chain (side chain tensioner)
- 9 Tensioning the Saw Chain (quick chain tensioner)
- 10 Checking Chain Tension
- 11 Fuel
- 12 Fueling
- 13 Chain Lubricant
- 14 Filling Chain Oil Tank
- 15 Checking Chain Lubrication
- 16 Chain Brake
- 17 Winter Operation
- 18 Starting / Stopping the Engine
- 18.1 Positions of Master Control Lever
- 18.2 Setting the Master Control Lever
- 18.3 Fuel pump
- 18.4 Holding the Saw
- 18.5 Cranking
- 18.6 Starting the Saw
- 18.7 When engine begins to fire
- 18.8 As soon as the engine runs
- 18.9 At very low outside temperatures
- 18.10 Stopping the engine
- 18.11 If the engine does not start
- 19 Operating Instructions
- 20 Taking Care of the Guide Bar
- 21 Shroud
- 22 Air Filter System
- 23 Cleaning the Air Filter
- 24 Adjusting the Carburetor
- 25 Spark Plug
- 26 Storing the Machine
- 27 Checking and Replacing the Chain Sprocket
- 28 Maintaining and Sharpening the Saw Chain
- 29 Maintenance and Care
- 30 Minimize Wear and Avoid Damage
- 31 Main Parts
- 32 Specifications
- 33 Ordering Spare Parts
- 34 Maintenance and Repairs
- 35 Disposal
- 36 EC Declaration of Conformity
► Reinstall the air filter.
23.1.4 Installing the Air Filter (round filter)
2710BA001 KN
2.
1.
► Place the air filter in position.
► Push the air filter in the direction of the filter
housing and turn it clockwise at the same time
until it engages – the "STIHL" name must be
horizontal.
► Install the shroud – see "Shroud".
23.1.5 Installing the Air Filter (synthetic fiber
filter)
► Place the air filter in position.
► Push the filter towards the filter housing until
the locking tabs snap into place.
► Install the shroud – see "Shroud".
24 Adjusting the Carburetor
24.1 Basic information
The carburetor comes from the factory with a
standard setting.
The carburetor has been adjusted for optimum
performance and fuel efficiency in all operating
states.
24.2 Standard setting
► Switch off the engine
► Check the air filter – clean or replace it if nec‐
essary
2310BA027 KN
► Turn the high speed adjusting screw (H) coun‐
terclockwise as far as possible (max. 3/4 turn)
► Turn the low speed adjusting screw (L) clock‐
wise until it is firmly in its seat – then back off
1/4 turn
24.3 Setting the idle speed
► Make standard setting
► Start engine and let it warm up
2310BA028 KN
24.3.1 Engine stops when idling
► Turn the idle speed adjusting screw (LA)
clockwise until the saw chain begins to run –
then turn it back 2 3/4 turn.
24.3.2 Saw chain rotates at idle speed
► Turn the idle speed screw (LA) counterclock‐
wise until the saw chain stops turning – then
turn another 2 3/4 turns in the same direction
WARNING
If the saw chain continues to keep rotating in idle
even after adjustment, have the chain saw
checked by a servicing dealer.
24.3.3 Speed erratic when idling; poor accel‐
eration (despite standard setting of low
speed adjusting screw)
The idle setting is too lean.
► Carefully turn the low speed adjusting
screw (L) counterclockwise until the engine
runs smoothly and accelerates properly.
Whenever the low speed adjusting screw (L) has
been adjusted, it is usually also necessary to
readjust the idle speed adjusting screw (LA).
24.4 Correcting the carburetor set‐
ting for use at high altitudes
The setting may have to be marginally corrected
if engine performance is unsatisfactory at high
altitudes:
► Make standard setting
► Let the engine warm up
24 Adjusting the Carburetor English
0458-737-0121-C 31