1995 Mariner Mercury Outboards Service Manual 50HP 4-Stroke, Page 150Get this manual
Inspection Cylinder Bore
MEASURING CYLINDER BORE
MEASURING PISTON
1Measure the piston at point 0.2 in (5.0 mm) from the bottom
1Measure the cylinder bore diameter lid" at three locations in both and axis
2It the cylinder bore is beyond the standard limits
listed in the tables below, it will be necessary to rebore the cylinder to accept the oversize piston[aPiston Diameter0.2 in(5.0 mm)
Piston Diameter "a" Cylinder Bore Specifications
Diameter (Standard) (Oversize) 0.020 in(0.50 mm)
Diameter (Standard) Taper or Out-ot-Round Maximum Limit Diameter 0.020 in(0.50 mm) Oversize Taper or Out-ot-Round Maximum Limit