1984-1986 Mercury Force 9.9 and 15HP Outboards Service Manual, Page 52Get this manual
4Inspection Crankshaft bearings and seals: ACheck upper and lower bearings for rustcracks, or wear BCheck upper and lower crankshaft seals for nicks, tearsor wearCRemove metal around lower main seal bore (peened over to retain seal)
5Inspection and repair cylinder head :
AClean carbon from spark plug threads in
cylinder head with spark plug tap (Special Tool No T2947)
BCheck flatness of cylinder head by laying
gasket surface on piece of plate glass or surface plate Figure 22
EMERY CLOTH
Figure 23Re.urfaclng Cylinder Head6Inspection and repairCylinder block and crankcase:
Measure the 1.0of cylinder bores at three points with an inside micrometer or dial indicatorMeasure 1(6.35 mm) down from top14(6.35 mm) up fr om exhaust port and about 316" (4.76 mm) down from lower edge of intake portMeasurements are also taken 90' from first set