Instruction Manual
Table Of Contents
- STIHL FS 91, 91 R
- 1 Guide to Using this Manual
- 2 Safety Precautions and Working Techniques
- 2.1 Clothing and equipment
- 2.2 Transporting the machine
- 2.3 Refueling
- 2.4 Before starting
- 2.5 Starting the engine
- 2.6 Holding and guiding the machine
- 2.7 While working
- 2.8 Using mowing heads
- 2.9 When using metal cutting attachments
- 2.10 Vibrations
- 2.11 Maintenance and Repairs
- 2.12 Symbols on Deflectors
- 2.13 Shoulder Strap/Harness
- 2.14 Mowing Head with Nylon Line
- 2.15 STIHL Polycut Mowing Head with Polymer Blades
- 2.16 Risk of Kickout (Blade Thrust) with Metal Cutting Attachments
- 2.17 Grass Cutting Blade
- 2.18 Brush Knife
- 2.19 Circular Saw Blade
- 3 Approved Combinations of Cutting Attachment, Deflector, Handle and Harness
- 4 Approved Power Tool Attachments
- 5 Mounting the Bike Handle
- 6 Mounting the Loop Handle
- 7 Adjusting the Throttle Cable
- 8 Fitting the Carrying Ring
- 9 Mounting the deflector
- 10 Mounting the Cutting Attachment
- 10.1 Placing power tool on the ground
- 10.2 Mounting Hardware for Cutting Attachments
- 10.3 Blocking the Shaft
- 10.4 Removing the Mounting Hardware
- 10.5 Mounting the Cutting Attachment
- 10.6 Fitting Mowing Head with Screw Mounting
- 10.7 Remove the mowing head.
- 10.8 Mounting Metal Cutting Attachments
- 10.9 Removing the Metal Cutting Attachment
- 11 Fuel
- 12 Fueling
- 13 Fitting the Harness
- 14 Balancing the Machine
- 15 Starting / Stopping the Engine
- 16 Transporting the Unit
- 17 Operating Instructions
- 18 Replacing the Air Filter
- 19 Adjusting the Carburetor
- 20 Spark Arresting Screen in Muffler
- 21 Spark Plug
- 22 Engine Running Behavior
- 23 Lubricating the Gearbox
- 24 Storing the Machine
- 25 Sharpening Metal Cutting Blades
- 26 Maintaining the Mowing Head
- 27 Maintenance and Care
- 28 Minimize Wear and Avoid Damage
- 29 Main Parts
- 30 Specifications
- 31 Maintenance and Repairs
- 32 Disposal
- 33 EC Declaration of Conformity
26.3 Adjusting Nylon Line
STIHL SuperCut
Fresh line is advanced automatically if the
remaining line is at least 6 cm (2 1/2 in) long.
The blade on the deflector trims overlong lines to
the correct length.
STIHL AutoCut
► With the engine running, hold the rotating
mowing head above the grass surface.
► Tap it on the ground once – fresh line is
advanced and the blade on the deflector trims
it to the right length.
Fresh line is advanced every time the mowing
head is tapped on the ground. For this reason
observe the mowing head's cutting performance
during operation. If the mowing head is tapped
on the ground too often, the line limiting blade
will unnecessarily cut off unused lengths of nylon
line.
Line feed operates only if both lines are still at
least 2.5 cm (1 in) long.
STIHL TrimCut
WARNING
To reduce the risk of injury, always shut off the
engine before adjusting the nylon line by hand.
► Pull the spool up – rotate it about 1/6 turn
counterclockwise until it engages – and allow it
to spring back.
► Pull ends of the lines outward.
Repeat the above procedure as necessary until
both lines reach the limiter blade on the deflec‐
tor.
Rotating the spool from one stop to the next
advances about 4 cm (1 1/2 in) of fresh line.
26.4 Replacing Nylon Line
STIHL PolyCut
Precut lengths of nylon line can be fitted to the
PolyCut in place of the cutting blades.
STIHL DuroCut, STIHL PolyCut
WARNING
To reduce the risk of injury, always shut off the
engine before refilling the mowing head.
► Fit precut lengths of nylon line in the mowing
head as described in the instructions supplied.
26.5 Replacing Cutting Blades
26.5.1 STIHL PolyCut
Always check the mowing head for signs of wear
before installing new cutting blades.
WARNING
If there are signs of serious wear, replace the
complete mowing head.
The thermoplastic cutting blades are referred to
as "blades" in the following.
The mowing head is supplied with illustrated
instructions for replacing the blades. Keep the
instructions for the mowing head in a safe place.
WARNING
To reduce the risk of injury, always shut off the
engine before installing the blades.
► Remove the mowing head.
► Replace blades as shown in the illustrated
instructions.
► Mount the mowing head on the machine.
English 26 Maintaining the Mowing Head
34 0458-426-8321-B