Honda BF15D BF20D Outboard Motors Shop Manual., Page 193Get this manual
bINSPECTION CYLINDER
1) Check the cylinder wall for scratches and wear
2) Measure and record the cylinder I.Dat three levels in both the and axisTake the maximum reading to determine the cylinder I.DX TOP
Standard 59.00059.012 mm (2.32282.3233 in)Service limit 59.055 mm (2.3250 in)
3) Check the cylinder head mating surface for warpage with straight edge and feeler gaugeStandard 0.05 mm (0.002 in)
Service limit 0.10 rnrn (0.004 in)
PISTONS
1) Inspect the piston for cracks or other damageInspect the ring grooves for excessive wear and carbon buildup2) Measure and record the piston Take measurements 10 mm (0.4 in) from the bottom, and 90" to the piston pin holeStandard-