Stihl MS 311, Manual, Page: 39 / 94

38 MS 311, MS 391
– Inspect the piston rings and
replace if necessary, b 6.8
– Check the oil seals and ball
bearings and replace if
necessary,
b 6.5
– Install the cylinder, b 6.5
– Reassemble all other parts in the
reverse sequence.
6.8 Piston Rings
– Remove the piston, b 6.7
– Remove the piston rings from the
piston.
: Use a piece of old piston ring to
scrape the grooves (arrows)
clean.
533RA134 TG
533RA135 TG
: Install the new piston rings in the
grooves so that the radii face
upward (arrows).
: Position the piston rings so that
the radii at the ring gap meet at
the fixing pin in the piston
groove (arrows).
: Check correct installed position
of the piston rings (arrows).
– Install the piston, b 6.7
– Reassemble all other parts in the
reverse sequence.
533RA136 TG
533RA137 TG
6.9 Decompression Valve
– Remove the shroud, b 6.4
: Unscrew the decompression
valve (1).
: Check the sealing cone (arrow)
on the decompression valve for
damage.
– If the sealing cone does not close
completely or shows signs of
damage, install a new
decompression valve.
– Fit the decompression valve and
tighten it down firmly.
– Reassemble all other parts in the
reverse sequence.
4903RA091 TG
1
165RA164 TG