Instruction Manual

MS 170, MS 170 C, MS 180, MS 180 C
English
7
After the saw has cooled appropriately,
follow the safety instructions in this
chapter for removing the cap.
Never remove the fuel filler cap by
turning it directly to the open position.
First check for residual pressure in the
tank by slowly turning the cap
approximately 1/2 turn counter-
clockwise. The cap should be held in
place by the threads while allowing
residual vapor/pressure to be relieved.
Once the fumes or vapor have been
relieved, turn the cap further until it can
be removed from the tank opening.
Use only good quality fuel that is
appropriate for the season (summer v.
winter blends). Some blends of
gasoline, particularly winter blends, are
more volatile and can contribute to fuel
spraying.
Removing the Threaded Fuel Filler Cap
WARNING
After allowing the chain saw to cool,
remove the fuel filler cap slowly and
carefully to allow any remaining
pressure build-up in the tank to release:
– While maintaining steady,
downward pressure, slowly turn the
cap approximately 1/2 turn counter-
clockwise.
– 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
only after the contents of the tank
are no longer under pressure.
– Never remove the cap by turning it
directly to the open position. First
allow the saw to cool adequately
and then release any residual
pressure by slowly turning it
approximately 1/2 turn counter-
clockwise.
– Never attempt to remove the cap
while the engine is still hot or
running.
Installing the Threaded Fuel Filler Cap
WARNING
Damaged or Broken Cap
If your fuel cap does not tighten properly,
it may be damaged or broken. Stop
using the chain saw and take it to your
authorized STIHL dealer for repair.
Vapor Lock
WARNING
Vapor lock occurs when fuel in the fuel
line or carburetor vaporizes, causing
bubbles to block the free flow of liquid
fuel into the carburetor. Vapor lock
cannot be relieved or affected by
opening the fuel tank. Removing the fuel
filler cap without first allowing the chain
saw to cool adequately can result in fuel
spraying. Always follow the instructions
in this section when removing the fuel
cap.
To relieve vapor lock:
– Place the Master Control Lever in
the cold start position l and pull
the starter cord approximately 20
times to clear the vapor and send
liquid fuel into the carburetor.
– To start the chain saw, move the
Master Control Lever to the starting
throttle position n and pull the
starter cord approximately 10 times.
– If your chain saw will not restart, or
if vapor lock occurs again, the chain
saw is being used in conditions too
extreme for the fuel being used.
Discontinue use and let the engine
cool completely before attempting
to start the chain saw.
Before Operation
Take off the chain guard (scabbard) and
inspect the chain saw for proper
condition and operation. (See the
maintenance chart near the end of the
instruction manual.)
WARNING
Always check your chain saw for proper
condition and operation before starting,
particularly the throttle trigger, throttle
trigger lockout, stop switch and cutting
attachment. The throttle trigger must
move freely and always spring back to
the idle position. The Master Control
Lever / stop switch must move easily to
STOP, 0 or †. Never attempt to modify
the controls or safety devices.
Unit vibrations can cause
an improperly tightened
fuel filler cap to loosen or
come off and spill quanti-
ties of fuel. To reduce the
risk of fuel spillage and
fire, tighten the fuel filler
cap by hand with as
much force as possible.