Adjusting The Carburetor - Stihl MS 391 Safety Manual

English
1
N
Push the clip (1) up and to the rear
and tilt the air filter toward the rear
handle and remove it
N
Always replace a damaged filter
For versions with "fleece filter with felt
prefilter"
2
1
N
Separate felt filter (1) from fleece
filter (2) – clean, see "Cleaning the
air filter"
Cleaning the air filter
N
Knock out the filter or blow it clear
with compressed air from the inside
outwards
In case of stubborn dirt:
N
Wash the filter in STIHL special-
purpose cleaner (special
accessories) or a clean, non-
flammable cleaning liquid (e.g.,
warm soapy water) and dry it
28
Do not clean fleece filters with a
brush!
The felt prefilter protects the fleece filter
and increases its service life. Thus it
should be replaced at shorter intervals
than the fleece filter.
Installing the air filter
2
1
N
Insert the lugs (1) into the
recesses (2)
N
Tilt the air filter toward the filter
housing and close the clip
N
Refit the shroud and tighten the
screws

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
correct the adjusting screws within fine
limits.
If the setting is too lean there is a
risk of engine damage due to
insufficient lubrication and
overheating.
Standard setting
LA
N
Shut off the engine
N
Check the air filter and clean or
replace if necessary.
N
Check the spark arresting screen
(country-specific) in the muffler and
clean or replace if necessary.
MS 311, MS 391