Instruction Manual

42
English / USA
MS 290, 310, 390
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.
: Check the air filter and replace if
necessary.
: Check the spark arresting screen
and clean or replace as necessary.
: Turn the high speed adjusting screw
(H) counterclockwise up to the stop,
i.e.
3
/
4
turn from max. lean setting.
: Turn the low speed adjusting screw
(L) clockwise up to the stop – then
back off the screw one quarter of a
turn.
Adjusting idle speed
Engine stops while idling
: Turn the idle speed adjusting screw
(LA) clockwise until chain begins to
run – then back off the screw one
quarter of a turn.
Chain runs when engine is idling
: Turn the idle speed adjusting screw
(LA) counterclockwise until chain
stops running – then turn screw
another quarter turn in the same
direction.
Adjusting the Carburetor
H
L
LA
139BA013 KN
4
L
H
3
1
/
4
/