Inspection - Mercury MerCruiser MCM 454 Mag MPI Service Manual

454 CID (7.4L) / 502 CID (8.2L)
5. Thoroughly clean valve guides with valve guide cleaner.

Inspection

1. Inspect cylinder heads for cracks in exhaust ports, water jackets and combustion cham-
bers (especially around spark plug holes and valve seats). Replace heads if any cracks
are found.
2. Inspect cylinder head gasket surface for burrs, nicks, erosion or other damage. Also,
check flatness of cylinder head gasket surface using a machinist's straight edge and
feeler gauges as shown. Refer to "Specifications."
IMPORTANT: Cylinder head-to-block gasket surface should be resurfaced if warped
more than specified. When head resurfacing is required, cylinder head-to-intake
manifold gasket surface on head must be milled to provide proper alignment
between intake manifold and head.
3. Inspect valves for burned heads, cracked faces or damaged stems.
4. Inspect rocker arm bolts and push rod guides for wear and damage.
Index
Page 3A-42
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a
a - Valve Guide Cleaner (J-8101)
a
a - Straight Edge
b - Feeler Gauge
c - Take Both Measurements Diagonally Across Head (Both Ways) And Straight
Down Center Of The Head
c
b
SERVICE MANUAL NUMBER 23
72564
72566
90-861326--1 MARCH 1999