Operation Manual

21BG 55, BG 65, BG 85, SH 55, SH 85
English / USA
General information
The carburetor comes from the factory
with a standard setting.
This setting provides an optimum fuel-air
mixture under most operating
conditions.
With this carburetor it is only possible to
adjust the engine idle speed within fine
limits.
Standard setting
: Shut off the engine.
: Turn high speed screw (H)
counterclockwise as far as stop
(max.
3
/
4
turn).
: Set the low speed screw (L) to one
full turn open.
Adjustment 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 the air filter and clean it if
necessary.
: Warm up the engine.
At high altitude
: Rotate the high speed screw (H)
clockwise (leaner) no further than
stop.
At sea level
: Rotate the high speed screw (H)
counterclockwise (richer) no further
than stop.
(With idle speed screw LA)
L
H
295BA044 KN