Stihl MS 660

44
English / USA
MS 650, MS 660
General Information
Your carburetor is preset at the factory
with the standard setting.
This setting is designed to provide an
optimum fuel-air mixture under most
operating conditions.
The high speed screw alters the
engine’s power output and the maximum
off-load engine speed.
If the setting is too lean there is
a risk of engine damage due to
insufficient lubrication and
overheating.
If the carburetor has to be adjusted from
scratch, first carry out the standard
setting.
Standard Setting
Carburetor with
H = 1 and
L = 1
: Shut off the engine.
: Check the air filter and clean or
replace if necessary.
: Check the spark arresting screen* in
the muffler and clean or replace if
necessary.
: Carefully screw both adjusting
screws down onto their seats
(clockwise).
: Open high speed screw (H) one full
turn.
: Open the low speed screw (L) one
full turn.
* see "Guide to Using this Manual"
Carburetor with
H =
3
/
4
and
L =
1
/
4
: Shut off the engine.
: Check the air filter and clean or
replace if necessary.
: Check the spark arresting screen* in
the muffler and clean or replace if
necessary.
: Turn high speed screw (H)
counterclockwise as far as stop (no
more than
3
/
4
turn)
: Turn the low speed screw (L)
clockwise as far as stop, then turn it
back
1
/
4
turn.
* see "Guide to Using this Manual"
Adjusting the Carburetor
L
H
176BA008 KN
L
H
137BA023 KN
L
H