Mercury MerCruiser Service Manual page 225

Production
4. Insert the appropriate type of piston ring into each of the piston ring grooves.
5. Roll the ring around the groove to ensure that the ring moves freely around the entire piston.
• If the ring binds, check the piston ring groove for deposits. Clean out all deposits.
• If the ring binds, check the piston ring groove for nicks or burrs. Minor internal damage can be dressed with a fine file.
• If the piston ring groove is clean and free of defects, check the groove with a different ring. The ring used for
inspection may be bent.
6. Using a feeler gauge, measure the clearance between the piston ring and the piston ring groove at several points around
the piston.
Groove clearance
90-8M0099748 eng DECEMBER 2015
Piston Bore Clearance
Description
Checking piston ring grooves
Measuring piston ring to piston clearance
Top Compression
Description
Production
Engine Inspection and Assembly
6.2 Liter (377 cid)
0.055–0.083 mm (0.0022–0.0032 in.)
19616
19618
6.2 Liter (377 cid)
0.030–0.075 mm (0.0012–0.0029 in.)
© 2016 Mercury Marine Page 3B-23