Yamaha Outboards 3P Service Manual, Page 41Get this manual
G6200 1-0'
PISTON Cleaning 1) Using gasket-scraper, remove the carbon from the piston top2) Using broken ring, clean the ring grooves
The top ring is keystone-type ring; therefore, do not use broken top ring for cleaning the other ring grooves, nor use broken ring from lower groove for cleaning the top groove3) Using soft brush and solvent, thoroughly clean the pistonIf necessary, use 600-800 grit wet-or-dry paper to remove score marks or varnish
Inspection 1) Using micrometer, measure the piston diameter at right angles to the piston-pin centreline, 10 mm (0.4 in) above the bottom edgePiston diameter: Standard: 45.96545.990 mm (1.8096-1.8106 in)