Stihl FS 91 R User Manual

Original Instruction ManualPrinted on chlorine-free paper
Printing inks contain vegetable oils, paper can be recycled.
© ANDREAS STIHL AG & Co. KG, 2020 0458-426-8621-A. VA7.G20. 0000007402_012_GB
FS 91, FS 91 R
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 trimmer /
brushcutter.
To receive maximum performance and
satisfaction from your STIHL trimmer /
brushcutter, 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 trimmer /
brushcutter. 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 trimmer / brushcutter is a
high-speed cutting tool some special
safety precautions must be observed to
reduce the risk of personal injury.
Careless or improper use may cause
serious or even fatal injury.
Make sure your unit is equipped with the
proper deflector or limit stop, handle and
harness for the type of cutting
attachment being used. Always wear
proper eye protection.
Guide to Using this Manual 2
Safety Precautions and Working
Techniques 3
Approved Combinations of Cutting
Attachment, Deflector, Limit Stop,
Handle, Harness 18
Approved Power Tool Attachments 20
Mounting the Bike Handle 20
Mounting the Loop Handle 22
Adjusting the Throttle Cable 23
Fitting the Carrying Ring 24
Mounting the deflector 24
Mounting the Cutting Attachment 25
Fuel 28
Fueling 30
Fitting the Harness 31
Balancing the Machine 32
Starting / Stopping the Engine 33
Transporting the Unit 36
Operating Instructions 37
Replacing the Air Filter 38
Engine Management 38
Adjusting the Carburetor 38
Spark Arresting Screen in Muffler 39
Spark Plug 39
Engine Running Behavior 40
Lubricating the Gearbox 41
Storing the Machine 41
Sharpening Metal Cutting Blades 41
Maintaining the Mowing Head 42
Maintenance and Care 44
Main Parts 46
Specifications 49
Maintenance and Repairs 50
Disposal 51
Limited Warranty 51
STIHL Incorporated Federal
Emission Control Warranty
Statement 51
STIHL Incorporated California
Exhaust and Evaporative
Emissions Control Warranty
Statement 53
Trademarks 55

Stihl FS 91 R Specifications

General

Type	String trimmer
Cordless	Yes
Head type	Nylon line
Handle type	D-loop handle
Engine power	1.3 hp
Product color	Black, Metallic, Orange
Uncertainty K	2 m/s²
Rotational speed	8000 RPM
Number of strokes	4
Sound power level	107 dB
Fuel tank capacity	0.71 L
Vibration emission	3.7 m/s²
Engine displacement	28.4 cm³
Sound pressure level	96 dB
Cutting diameter (max)	- mm
Power source	Gasoline

Weight and Dimensions

Length	1800 mm
Weight	5500 g