Fuel - Stihl FS 91 Manual De Instrucciones

English
14
13
10
11
12
Fit the thrust plate (9).
N
Place the cutting attachment (8) on
N
the thrust plate (9).
Collar (see arrow) must engage the
cutting attachment's mounting hole.
Securing the Cutting Attachment
Fit the rider plate (10).
N
Block the shaft (11) with the stop pin
N
(12).
Use the combination wrench (14) to
N
screw the mounting nut (13) on to
the output shaft counterclockwise
and tighten it down firmly.
WARNING
There is a risk of injury if the cutting
attachment works loose. If the mounting
nut has become too loose, fit a new one.
28
NOTICE
Remove the tool used to block the shaft.
Removing the Metal Cutting Attachment
WARNING
Wear protective gloves to reduce the
risk of direct contact with the sharp
8
cutting edges.
Block the shaft (11) with the stop pin
N
9
(12).
Unscrew the mounting nut (13)
N
clockwise.
Remove cutting attachment and its
N
mounting hardware from the
gearbox – but do not remove the
thrust plate (9).

Fuel

This engine is certified to operate on
unleaded gasoline and the STIHL two-
stroke engine oil at a mix ratio of 50:1.
Your engine requires a mixture of high-
quality gasoline and two-stroke air
cooled engine oil.
Use mid-grade unleaded gasoline with a
minimum octane rating of 89 ((R+M)/2)
and no more than 10% ethanol content.
Fuel with an octane rating below 89 may
increase engine temperatures. This, in
turn, increases the risk of piston seizure
and damage to the engine.
The chemical composition of the fuel is
also important. Some fuel additives not
only detrimentally affect elastomers
(carburetor diaphragms, oil seals, fuel
lines, etc.), but magnesium castings and
catalytic converters as well. This could
cause running problems or damage the
engine. For this reason STIHL
recommends that you use only quality
unleaded gasoline!
Gasoline with an ethanol content of
more than 10% can cause running
problems and major damage in engines
and should not be used.
For further details, see
www.STIHLusa.com/ethanol
The ethanol content in gasoline affects
engine speed – it may be necessary to
readjust the carburetor if you use fuels
with various ethanol contents.
FS 91, FS 91 R