Owner's Manual

21BR 340, BR 340 L, BR 420, BR 420 C
English / USA
Standard Setting
: Shut off the engine.
: Turn the high speed screw (H) and
low speed screw (L) counter-
clockwise as far as stop (max.
1
/
4
turn).
Adjusting Idle Speed
Engine stops while idling
: Carry out standard setting on the
low speed screw.
: Turn idle speed screw (LA)
clockwise until the engine runs
smoothly.
Erratic idling behavior, poor
acceleration
: Carry out standard setting on the
low speed screw.
: Turn low speed screw (L)
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 at High
Altitude or at Sea Level
A slight correction of the setting may be
necessary if engine power is not
satisfactory when operating at high
altitude or at sea level:
: Check standard setting.
: Warm up the engine.
: Turn the high speed screw (H)
slightly clockwise (leaner) – on
models with limiter caps (H = 1/4),
no further than stop.
If the setting is too lean, there is a
risk of engine damage due to
insufficient lubrication and
overheating.
H
L
373BA043 KN
LA
L
373BA044 KN