Safety Manual

Original Instruction ManualPrinted on chlorine-free paper
Printing inks contain vegetable oils, paper can be recycled.
© ANDREAS STIHL AG & Co. KG, 2020 0458-737-8621-B. VA5.G20. 0000006612_012_GB
MS 251, MS 251 C
English
1
This instruction manual is protected by copyright. All rights reserved, especially the rights to reproduce, translate and process
with electronic systems.
Contents
Allow only persons who fully understand
this manual to operate your chain saw.
To receive maximum performance and
satisfaction from your STIHL chain saw,
it is important that you read, understand
and follow the safety precautions and
the operating and maintenance
instructions in chapter "Safety
Precautions and Working Techniques"
before using your chain saw. For further
information you can go to
www.stihlusa.com.
Contact your STIHL dealer or the STIHL
distributor for your area if you do not
understand any of the instructions in this
manual.
WARNING
Because a chain saw is a high-speed
wood-cutting tool, some special safety
precautions must be observed as with
any other power saw to reduce the risk
of personal injury. Careless or improper
use may cause serious or even fatal
injury.
Guide to Using this Manual 2
Safety Precautions and Working
Techniques 3
Cutting Attachment 27
Mounting the Bar and Chain (side
chain tensioner) 28
Mounting the Bar and Chain (quick
chain tensioner) 29
Tensioning the Saw Chain (side
chain tensioner) 31
Tensioning the Saw Chain (quick
chain tensioner) 31
Checking Chain Tension 31
Fuel 32
Fueling 33
Chain Lubricant 36
Filling Chain Oil Tank 36
Checking Chain Lubrication 37
Chain Brake 37
Winter Operation 38
Starting / Stopping the Engine 39
Operating Instructions 43
Taking Care of the Guide Bar 44
Shroud 45
Air Filter System 45
Cleaning the Air Filter 45
Engine Management 46
Adjusting the Carburetor 47
Spark Arresting Screen in Muffler 48
Spark Plug 48
Storing the Machine 49
Checking and Replacing the Chain
Sprocket 50
Maintaining and Sharpening the
Saw Chain 51
Maintenance and Care 55
Main Parts 57
Specifications 59
Ordering Spare Parts 60
Maintenance and Repairs 60
Disposal 61
Limited Warranty 61
STIHL Incorporated Federal
Emission Control Warranty
Statement 61
Trademarks 64