Mercury MerCruiser Service Manual page 247

Description
Surface flatness
7. If a measured value is greater than specified, the cylinder head must be repaired to specifications or replaced.
Valve
1. Inspect the valves for burned heads, cracked or pitted faces, or damaged stems.
a
IMPORTANT: Excessive valve stem to bore clearance will cause excessive oil consumption and possibly broken valves.
Insufficient clearance will result in noisy, binding valves.
2. Measure the valve stem diameter in three places.
3. If the measured value is less than the specified limit, the valve must be replaced.
Description
Production stem diameter
4. Measure the valve head margin.
5. If the measured value is less than specified, the valve must be replaced.
90-8M0099748 eng DECEMBER 2015
At exhaust manifold deck
At engine block deck with
an 150 mm (5.90 in.) area
At intake manifold deck
Intake manifold flatness
b
32988
Intake
Exhaust
© 2016 Mercury Marine
Engine Inspection and Assembly
6.2 Liter (377 cid)
0.05 mm (0.0020 in.)
0.05 mm (0.0020 in.)
0.10 mm (0.0039 in.)
0.10 mm (0.0039 in.)
a - Cracked and pitted face
b - Damaged stem
32989
6.2 Liter (377 cid)
7.96 mm (0.3133 in.)
7.97 mm (0.3137 in.)
32997
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