2005 SO Johnson 4 Stroke 9.9-15HP Outboards Service Manual, Page 156Get this manual
POWERHEAD CYLINDERCRANKCASEPISTON ASSEMBLY Pistons and Rings Measure piston ring to groove clearance after decarbonizingStandard piston ring groove width: 1st and 2nd rings: 0.0476 to 0.0484 in(1 .21 to 1.23 mm) Oil ring: 0.0988 to 0.0996 in(2.51 to 2.53 mm) Standard piston ring thickness: 1st and 2nd rings: 0.0461 to 0.0469 in (1.17 to 1.19mm) Piston ring to groove clearance: Standard: 1st and 2nd rings, 0.0008 to 0.0024 in(0.02 to 0.06 mm) Service limit: 1st and 2nd rings, 0.004 in(0.10 mm) If measurement exceeds service limit, replace the piston andor piston ring004575