Yamaha Outboard Motors Factory Service Manual F6 and F8, Page 292Get this manual
CRANKSHAFT, PISTON AND CYLINDER BODY CHECKING THE PISTON RING
1Measure: End gap Out of specification piston ringReplace the
Top ring end gap: 0.150.30 mm(0.0060.012 in) 2nd ring end gap: 0.300.45 mm(0.0120.018 in) Oil ring end gap: 0.200.70 mm(0.0080.028 in)