Zenoah GZ4500 - Manual (Page 10)

GZ4500
GB-10
Carburetor anti-freeze mechanism
Operating chain saws in temperatures of 0 – 5°C at times of
high humidity may result in ice forming within the carburetor,
and this in turn may cause the output power of the engine to
be reduced or for the engine to fail to operate smoothly.
This product has accordingly been designed with a ventila-
tion hatch on the right side of the surface of the cylinder cover
to allow warm air to be supplied to the engine and to thereby
prevent icing from occurring.
Under normal circumstances the product should be used in
the normal operating mode, i.e., in the mode to which it is set
at the time of shipment. However when the possibility exists
that icing may occur, the unit should be set to operate in the
anti-freeze mode before use. Please switch between modes
in the repair specialty store.
Continuing to use the product in the anti-freeze
mode even when temperatures have risen and
returned to normal, may result in the engine
failing to start properly or in the engine failing
to operate at its normal speed, and for this
reason you should always be sure to return
the unit to the normal operating mode if there
is no danger of icing occurring.
1. Stop engine and screw L needle until it stops. Never
force. Then set it back the initial number of turns as
shown below. H needle is restricted within the num-
ber of turn as shown below.
H needle : - 1 /
4
L needle : 2 3 /
8
± 1 /
2
2. Start the engine and allow it to warm up in low speed
for a few minutes.
3. Turn L needle slowly clockwise to find a position
where idling speed is maximum, then set the needle
back a quarter (1/4) turn counterclockwise.
4. Turn the idle adjusting screw (T) counterclockwise
so that the saw chain does not turn. If the idling
speed is too slow, turn the screw clockwise.
5. Make a test cut and adjust the H needle for best
cutting power, not for maximum speed.
■ CHAIN BRAKE
This machine is equipped with an automatic brake to
stop saw chain rotation upon occurrence of kickback
during saw cutting. The brake is automatically operated
by inertial force, which acts on the weight fitted inside
the front guard.
This brake can also be operated manually with the front
guard turned down to the guide bar.
To release the brake, pull up the front guard toward the
front handle till a “click” sound is heard.
[Caution]
Be sure to confirm brake operation during daily inspec-
tion.
How to confirm:
1) Turn off the engine.
2) Holding the chain saw horizontally, release your hand
from the front handle, hit the tip of the guide bar to a
stump or a piece of wood, and confirm brake op-
eration. Operating level varies by bar size.
In case the brake is not effective, ask our dealer for
inspection and repairs.
If the engine keeps rotating at high speed with the brake
engaged, the clutch will overheat causing trouble.
When the brake engages during operation, immediately
release the throttle lever to stop the engine.
■ STOPPING THE ENGINE
1. Release the throttle lever to allow the engine to idle
for a few minutes.
2. Set the switch to the “O” (STOP) position.
Normal operating mode Anti-freeze mode
Cylinder cover
“Sunshine” mark “Snow” mark
Switch