Yamaha Outboards 3P Service Manual, Page 42Get this manual
G62501-0'
PISTON RING Inspection 1) Using feeler gauge, measure the clearance between the piston ring and the groove landSide clearance: Top ring: 0.020.06 mm (0.00080.0024 in) 2nd: 0.030.07 mm (0.00120.0028 in) If the clearance is not within the specifications, replace the piston
IAl Top IBJ 2nd
2) Insert the piston ring into the cylinderUsing piston, push the piston ring little beyond the bottom of the ring travel to depth of 20 mm (0.8 in) from the top of the cylinder block