Air Valve - Stihl MS 171 Manual

14.4.6 Air Valve

Air valve shaft stiff or air valve
cannot be closed or opened
properly:
– Remove the carburetor, b 14.3
– Carburetor troubleshooting,
Checking position of throttle
shutter (position of throttle
trigger)/air valve
The correct position of the air valve
can be checked visually as follows:
– Throttle shutter in idle position
– air valve completely closed.
– Throttle shutter between idle
position and full throttle – air
valve between closed and wide
1)
open
– Throttle shutter in full throttle
position – air valve wide open
– Throttle shutter during cold start
in l position
– air valve completely closed
– Throttle shutter during warm start
in k position – air valve open
about 10°
1)
It must be possible to move the
air valve in both directions and
it must always return to its
starting position
MS 171, MS 181, MS 211
All manuals and user guides at all-guides.com
2
Lever (1) must butt against lever (2)
and engage lever (3).
Screw (arrow) must be tightened
down firmly.
The edge of the end cover must be
in line with the edge of the
carburetor body.
The side of the levers (2+3) must
not touch each other.
Clearance "a" = about 0.3 mm,
b 14.4.1
1)
The torsion springs (arrows) be
preloaded when attached to the
levers.
Removing and Installing
3
1
: Remove the screw (arrow).
1
2
: Turn the air valve shaft (1) and
pull out the air valve (2).
1
2
: Remove the E-clip (arrow).
– Pull out the air valve shaft (1) and
disconnect and relax the torsion
spring (2) at the same time.
– Clean the air valve shaft and
guides, b 16
79