Stihl MS 661 C-M Instruction Manual

0458-759-8221-C
41
English 13 Mixing Fuel and Refueling the Chain Saw
WARNING
Removing the fuel cap on a pressurized fuel tank can result
in gasoline, vapors and fumes being forcefully sprayed out
from the tank in all directions. The escaping gasoline, vapors
or fumes, sometimes referred to as fuel spraying or
“geysering,” can cause serious personal injury, including fire
and burn injury, or property damage, @ 5.5.
WARNING
Fuel spraying can occur when the engine is hot and the tank
is opened while under pressure. It can occur in hot
environments even if the engine has not been running.
Spraying is more likely to occur when the fuel tank is half full
or more. Always follow the fueling instructions in this
manual:
– Treat every fuel tank as if it is pressurized, particularly
if it is half full or more.
– Always allow the chain saw to cool adequately before
attempting to open the fuel tank or refueling. This will
take longer in hot conditions.
– Never remove the cap by turning it directly to the open
position. Turn it first approximately 1/8 of a turn
counter-clockwise to the vent position to relieve any
residual pressure.
– Never open the fuel tank while the engine is still hot or
running.
– Never open the fuel tank or re-fuel the saw near any
sparks, flames or other ignition sources.
– Pick the right fuel: use only good quality (89 octane or
higher), fresh fuel blended for the season.
– Vapor lock: do not remove the fuel cap in an effort to
relieve vapor lock. Removing the cap has no effect on
vapor lock.
– Be aware that fuel spraying is more likely at higher
altitudes.
Opening and Refueling
To refuel the chain saw:
► Shut off the engine, @ 15.
► Engage the chain brake, @ 12.1.
► Allow the chain saw to cool. Never attempt to remove the
cap while the engine is still hot or running.
► Position the chain saw on a level surface with the fuel filler
cap facing upwards.
► Clean the area around the fuel filler cap with a slightly
dampened cloth.
► Flip up the grip and press the cap down firmly (1).
► While maintaining steady, downward pressure, turn the
cap slowly counter-clockwise to the vent position (2),
approximately a 1/8 turn of the cap. Never remove the cap
by turning it directly to the open position.
► If any significant venting occurs, immediately re-seal the
tank by turning the cap clockwise to the closed position.
Allow the saw to cool further before attempting to open the
tank.
► Turn the cap to the open position (3) only after the
contents of the tank are no longer under pressure. In the
open position, the exterior positioning mark (4) on the cap
will line up with the "unlocked" symbol (5) on the fuel tank
housing.
► Remove the fuel filler cap and fill the tank with fuel.
► Take care not to spill fuel while refilling the tank.
► Do not overfill the tank. Leave approximately 0.5 in.
(13 mm) of air space.
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Stihl MS 661 C-M Specifications

General

Idle speed	- RPM
Motor type	2-stroke motor
Chain pitch	3/8 \
Blade length	800 mm
Product color	Black, Grey, Orange
Automatic oiling	Yes
Engine displacement	91.1 cm³
Power source	Gasoline
Sound power level	118 dB
Vibration emission	6.9 m/s²
Sound pressure level	105 dB

Weight and Dimensions

Weight	7400 g