Stihl BR 450 User Manual

BR 450, BR 450 C
English
23
Erratic idling behavior, engine stops
even though setting of LA screw has
been corrected, poor acceleration
Idle setting is too lean
N Turn the low speed screw (L)
counterclockwise, no further than
stop, until the engine runs and
accelerates smoothly.
Erratic idling behavior
Idle setting is too rich
N Turn the low speed screw (L)
clockwise, no further than stop, 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 at High
Altitude
A slight correction of the setting may be
necessary if the engine does not run
satisfactorily:
N Carry out the standard setting.
N Warm up the engine.
N Turn high speed screw (H) slightly
clockwise (leaner) – no further than
stop.
NOTICE
After returning from high altitude, reset
the carburetor to the standard setting.
If the setting is too lean there is a risk of
engine damage due to insufficient
lubrication and overheating.
If there is a loss of engine power, the
machine is difficult to start or runs poorly
at idle, first check the spark plug.
Install a new spark plug after
approximately 100 operating hours or
earlier if the electrodes are
eroded/corroded.
The wrong fuel mix (too much engine oil
in the gasoline), a dirty air filter and
unfavorable running conditions (mostly
at part throttle etc.) affect the condition
of the spark plug. These factors cause
deposits to form on the insulator nose,
which may degrade performance.
Removing the spark plug
N Pull off the spark plug boot (1)
vertically.
N Unscrew the spark plug (2).
Checking the Spark Plug
N Clean dirty spark plug.
N Check electrode gap (A) and
readjust if necessary – see chapter
"Specifications."
N Use only resistor type spark plugs of
the approved range.
Rectify problems which have caused
fouling of spark plug:
– too much oil in fuel mix,
– dirty air filter,
– unfavorable running conditions, e.g.
operating at part load.
Spark Plug
2
0002BA049 KN
000BA039 KN
A
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Stihl BR 450 Specifications

General

Type	Backpack blower
Airflow	1430 m³/h
Airspeed	298.8 km/h
Suction mode	-
Shoulder strap	Yes
Power source	Gasoline
Sound power level	108 dB
Vibration emission	2.5 m/s²
Sound pressure level	102 dB

Weight and Dimensions

Weight	10600 g