Instruction Manual

30.2 Ignition System
Electronic magneto ignition
Spark plug (resistor type): Bosch USR 7 AC
Electrode gap: 0.5 mm
30.3 Fuel System
All position diaphragm carburetor with integral
fuel pump
Fuel tank capacity:
710 cc (0.71 l)
30.4 Weight
Dry, without cutting attachment and deflector
FS 91: 5.8 kg
FS 91 R: 5.5 kg
30.5 Overall length
without cutting attachment 1800 mm
30.6 Features
R Loop handle
30.7 Noise and Vibration Data
30.7.1 Cutting Attachment
For details on compliance with Vibration Direc‐
tive 2002/44/EC visit www.stihl.com/vib.
Sound pressure level L
p
to ISO 22868
with mowing head
FS 91 with bike handle: 95 dB(A)
FS 91 R: 95 dB(A)
with metal mowing attachment
FS 91 with bike handle: 93 dB(A)
FS 91 R with barrier bar: 93 dB(A)
Sound power level L
w
to ISO 22868
with mowing head
FS 91 with bike handle: 106 dB(A)
FS 91 R: 106 dB(A)
with metal mowing attachment
FS 91 with bike handle: 105 dB(A)
FS 91 R with barrier bar: 105 dB(A)
Vibration level a
hv,eq
to ISO 22867
with mowing head Handle, left Handle,
right
FS 91 with bike han‐
dle:
3.4 m/s
2
3.0 m/s
2
FS 91 R:
5.3 m/s
2
5.3 m/s
2
with metal mowing
attachment
Handle, left Handle,
right
FS 91 with bike han‐
dle:
3.2 m/s
2
2.5 m/s
2
FS 91 R with barrier
bar:
3.8 m/s
2
4.3 m/s
2
30.7.2 Interchangeable Attachments
The noise and vibration data of the approved
attachments are listed in the instructions sup‐
plied with each attachment.
The K‑factor in accordance with Directive
2006/42/EC is 2.0 dB(A) for the sound pressure
level and sound power level; the K‑factor in
accordance with Directive 2006/42/EC is
2.0 m/s
2
for the vibration level.
30.8 REACH
REACH is an EC regulation and stands for the
Registration, Evaluation, Authorisation and
Restriction of Chemical substances.
For information on compliance with the REACH
regulation (EC) No. 1907/2006 see
www.stihl.com/reach.
30.9 Exhaust Emissions
The CO
2
value measured in the EU type approval
procedure is specified at www.stihl.com/co2.
The measured CO
2
value was determined on a
representative engine in accordance with a
standardized test procedure under laboratory
conditions and does not represent either an
explicit or implied guarantee of the performance
of a specific engine.
The applicable exhaust emission requirements
are fulfilled by the intended usage and mainte‐
nance described in this instruction manual. The
type approval expires if the engine is modified in
any way.
31 Maintenance and Repairs
Users of this machine may only carry out the
maintenance and service work described in this
user manual. All other repairs must be carried
out by a servicing dealer.
STIHL recommends that you have servicing and
repair work carried out exclusively by an author‐
ized STIHL servicing dealer. STIHL dealers are
regularly given the opportunity to attend training
courses and are supplied with the necessary
technical information.
When repairing the machine, only use replace‐
ment parts which have been approved by STIHL
for this power tool or are technically identical.
Only use high-quality replacement parts in order
to avoid the risk of accidents and damage to the
machine.
English 31 Maintenance and Repairs
38 0458-426-8321-B