Spark Plug - Stihl FR 480 C Instruction Manual

English
L
H
1
3/4
LA
N Turn high speed screw (H)
counterclockwise as far as stop (no
more than 3/4 turn).
N Turn the low speed screw (L)
carefully clockwise until it is against
its seat, then turn it back 1 full turn.
N Warm up the engine.
N Adjust idle speed with the idle speed
screw (LA) so that the cutting
attachment does not rotate.
Adjusting Idle Speed
Engine stops while idling
N
Carry out the standard setting.
N Turn the idle speed screw (LA)
slowly clockwise until the engine
runs smoothly – the cutting
attachment must not rotate.
Cutting attachment rotates when
engine is idling
N Carry out the standard setting.
N Turn the idle speed screw (LA)
counterclockwise until the cutting
attachment stops moving and then
rotate the screw another 1/2 to 1
turn in the same direction.
28
Erratic idling behavior, poor
acceleration
Idle setting is too lean.
N Carry out the standard setting.
N Turn the low speed screw (L) slowly
counterclockwise until the engine
runs and accelerates smoothly.
It is usually necessary to change the
setting of the idle speed screw (LA) after
every correction to the low speed
screw (L).
Fine Tuning for Operation in
Mountains or at Sea Level
A slight correction of the setting of the
high speed screw (H) may be necessary
if engine power is not satisfactory when
operating at high altitude or at sea level.
N Check the standard setting.
N Warm up the engine.
N Adjust idle speed properly.
At high altitude
N
Turn high speed screw (H)
clockwise (leaner) – no further than
stop.
At sea level
N Turn high speed screw (H)
counterclockwise (richer) – no
further than stop.
If the setting is too lean there is a
risk of engine damage due to
insufficient lubrication and
overheating.

Spark Plug

N
If the engine is down on power,
difficult to start or runs poorly at idle
speed, first check the spark plug.
N Fit a new spark plug after about 100
operating hours – or sooner if the
electrodes are badly eroded. Install
only suppressed spark plugs of the
type approved by STIHL – see
"Specifications".
Removing the spark plug
N Move the slide control to STOP-0
(h).
N Pull off the spark plug boot (1).
N Unscrew the spark plug.
FR 480 C