Stopping The Chainsaw; Checking The Oil Supply; Adjusting The Carburettor; Chain Brake - GMC PCH25 Instruction Manual

25.4cc compact chain saw
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11. When ready to start cutting, release the brake, by
pulling the front guard back.

Stopping the chainsaw

1. Release the trigger switch.
2. Set the on/off switch (18) to
Off (the O position).

Checking the oil supply

Run the engine at medium
speed and check that the chain
splatters a thin line of oil which
can be seen on the ground when
the bar is pointed downwards.
This is normal. If there is no
line of chain oil, stop the motor
immediately and investigate the
cause. The oil tank could be
empty or the oil supply to the
chain blocked. This may require
removal of the bar and checking
that the upper oil hole in the bar
is clear of any blockages.

Adjusting the carburettor

The carburettor is factory set and
should not require adjustment.
Changes in operating conditions
may require fine tuning of the
carburettor. Proceed as follows.
1. Stop the engine and screw in
both the H and L needles (15)
using screwdriver (28). Do not
force.
2. Turn the H screw (15) back 3/4 of a turn.
3. Turn the L screw (16) back 1-1/2 turns.
4. Start the engine and let it warm up with the trigger switch
half pulled in. When the engine is warm, release the
trigger switch.
5. Turn the L screw (17) slowly clockwise until the idling
speed is at its maximum then turn the screw back
(anticlockwise) 1/4 of a turn.
6. Turn the idling adjusting screw (T) (14) anticlockwise until
the chain does not turn.
7. If the idling speed is too slow, turn screw (T) clockwise.
8. Make a test cut and adjust screw (15) for best cutting
power, not for maximum speed.

Chain brake

The chain brake operates automatically in the event of
kickback. As the guide bar (1) kicks up, the wrist of the
operator's hand on the top handle knocks against the front
guard (8) causing the front guard to move forward and
activating the chain brake.
1. The chain brake can be
operated manually by moving
the front guard forward.
2. To release the chain brake,
pull the front guard towards
the top handle until a "click"
is heard.
CAUTION. Check that the chain
brake is operating correctly each time the chainsaw is used.
H
L
T

Bucking spikes

The Chainsaw has bucking
spikes (6) to assist with cutting
and reduce the chance of
kickback, use them as follows:
12

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