Stihl 4180 Series Service Manual page 85

Rotate the crankshaft clockwise until the cam lobe
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points downwards.
Check that mark on flywheel lines up with the right-
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hand screw on the ignition module.
The two arrows on the cam gear (8) must line up with the
two notches in the cylinder.
Fit the cover (8) before adjusting the valves.
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Checking, adjusting valve clearance
16
14
21
23
Insert feeler gauge 4180 893 6400 (23) between
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rocker arm (14) and valve stem (21).
The feeler gauge must slip through with a certain
resistance.
Adjust valve clearance with the two nuts (16):
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Inlet valve = 0.10 +- 0.02 mm
Exhaust valve = 0.10 +- 0.02 mm
To increase valve clearance: Turn nut counterclockwise.
To reduce valve clearance: Turn nut clockwise.
Rotate crankshaft several times and then check valve
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clearance again.
Apply Dirko sealant to groove in cover (8).
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Fit the cover (8).
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Insert and tighten down the screws (9).
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Fit gasket (17) in the valve cover (18).
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Place valve cover (18) in position, fit screw (20) with
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new sealing ring (19) and tighten down.
Fit the starter cup (11) and tighten down the nut (10).
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Insert and tighten down the spark plug.
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Fit the spark plug boot.
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Install the shroud, @ 4.3.
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Series 4180 Powerhead
7
16
14
22
41