Stihl 038 - Rim sprocket

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Remove the oil pump drive worm (8) from the pump shaft
by turning it clockwise and pulling it at the same time. The
chain sprocket (7) can now be pulled off the crankshaft to-
gether with the spur gear (9) and needle cage. The spur
gear (9) can be prised off the chain sprocket (7) with the
aid of two screwdrivers.
Clean the stub of the crankshaft, wash the needle cage,
spur gear (9) and worm (8) in clean gasoline. Lubricate the
needle cage with STIHL multipurpose grease.
Reverse the above sequence for reassembly. Examine
spur gear (9) and worm (8) for worn or broken teeth and re-
place if necessary. Coat the teeth of the spur gear and
worm with STIHL multipurpose grease when installing.
The circlip (6) must be fitted so that both its ends locate on
the top of a tooth as illustrated.
Rim sprocket
First remove the chain sprocket cover, Oilomatic chain and
guide bar.
Insert a pointed knife or similar too! behind the E-clip (8) to
ease it clear of the warts on the thrust washer (10) and
then use a small screwdriver to prise the E-clip off the
crankshaft. Take off the thrust washer and rim sprocket
(11).
Fit the new rim sprocket so that the side with the cavities
faces outward.
Finish off by refitting the thrust washer (10) and E-clip (3)
on the crankshaft.
Only original STIHL clutch drums may be installed.
Top: Removing the drive worm
Center: Circlip correctly fitted
Bottom: Rim sprocket in position