Motor Management; Adjusting The Carburetor - Stihl MS 390 Instruction Manual

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: Pull prefilter (1) upward and out.
: Unscrew slotted nuts (2).
: Remove main filter (3).
: Separate the two halves of the filter.
: Knock the filter out on the palm of
your hand or blow it out with
compressed air from the inside
outward.
In case of stubborn dirt:
: Wash with STIHL universal cleaner
or in a clean, non-flammable
cleaning solution (e.g. warm soapy
water) and dry all parts of the filter.
Never use a brush to clean the fleece
filter element
: Always replace damaged
filterelements.
: Reinstall the filters.
MS 290, MS 310, MS 390

Motor Management

Exhaust emissions are controlled by the
design of the fundamental engine
parameters and components (e.g.
carburation, ignition, timing and valve or
port timing) without the addition of any
major hardware.
English / USA

Adjusting the Carburetor

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!
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