Adjusting The Carburetor; General Information; Adjusting Idle Speed - Stihl BT 121 Manual De Instrucciones

English / USA

Adjusting the Carburetor

General Information

Your 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 high speed screw within fine
limits.
Standard Setting
: Shut down the engine.
: Remove the auger from the
machine.
: Check air filter and clean or replace
as necessary.
: Check that the throttle cable is
properly adjusted and readjust if
necessary – see chapter on
"Adjusting the Throttle Cable".
20
L
H
1
LA
: Turn the high speed screw (H)
counterclockwise as far as stop
3
– max. / turn
4
: Carefully turn the low speed
screw (L) down onto its seat
clockwise. Then open it one turn
counterclockwise.
: Start and warm up the engine.
: Adjust idle speed with the idle speed
screw (LA) so that the drilling
spindle does not rotate.

Adjusting Idle Speed

Engine stops while idling
: Carry out standard setting with the
low speed screw (L).
: Turn the idle speed screw (LA)
clockwise until the engine runs
smoothly – the drilling spindle must
not rotate.
Drilling spindle rotates when engine
is idling
: Turn the idle speed screw (LA)
counterclockwise until the drilling
spindle stops rotating – then turn the
screw about another half to one full
turn in the same direction from that
position.
BT 121