Stihl MS 231 Manual page 40

1
2
: Release the crankshaft (1) from
the bearing seats (arrows) in the
cylinder (2) and pull it out
together with the piston.
1
1
: Pull off the oil seals (1)
– always install new oil seals.
1
: Remove sealant from the sealing
face (arrows) on the engine
pan (1).
– Inspect and clean the sealing
face, b 14
MS 231, MS 231 C, MS 251, MS 251 C
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2
1
2
– Inspect the intake manifold (1)
and replace it if necessary – even
very minor damage can result in
engine running problems, b 3.7
: Take out the screws (2).
: Remove the intake manifold (1).
1
: Remove sealant and gasket
residue from the sealing
faces (arrows) of the cylinder (1).
– Inspect and clean all sealing
faces, b 14
When reinstalling the cylinder,
always seal it with fresh sealant on
the engine pan.
– Inspect the piston and piston
rings and replace if necessary,
b 6.8, b 6.9
If the piston or the oil seals are
2
damaged, also inspect the inside of
the cylinder for signs of damage and
install a new cylinder if necessary.
Installing
1
: Fit the manifold (1) in position.
: Insert and tighten down the
Use soft oil seal (1) 9638 003 1581
with snap ring for replacement on
closed engine.
Use hard oil seal (2) 9639 003 951
without snap ring for replacement
on opened engine.
Install the soft oil seal with the snap
ring facing outwards and the hard oil
seal with its open side facing the
ball bearing.
2 2
2
screws (2) firmly.
2
1
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