Mercury FourStroke 2.5, Service Manual, Page: 84 / 205

Powerhead
90-8M0065421 NOVEMBER 2012 Page 4A-3
Piston Specifications
Piston Specifications
Piston outside diameter (standard) 54.96 mm (2.1638 in.)
Piston outside diameter (service limit) 54.90 mm (2.1614 in.)
Piston clearance (standard) 0.020–0.06 mm (0.0008–0.0024 in.)
Piston clearance (service limit) 0.15 mm (0.0059 in.)
Piston ring side clearance (standard)
Top
0.04–0.08 mm (0.0016–0.0031 in.)
Middle 0.03–0.07 mm (0.0012–0.0028 in.)
Bottom 0.05–0.15 mm (0.002–0.0059 in.)
Piston ring side clearance (service limit)
Top
0.10 mm (0.0039 in.)
Middle 0.09 mm (0.0035 in.)
Bottom 0.17 mm (0.0067 in.)
Piston ring end gap (standard)
Top
0.15–0.30 mm (0.0059–0.0118 in.)
Middle 0.30–0.45 mm (0.0118–0.0177 in.)
Bottom 0.20–0.70 mm (0.0079–0.0276 in.)
Piston ring end gap (service limit)
Top
0.5 mm (0.0197 in.)
Middle 0.7 mm (0.0276 in.)
Piston pin diameter (standard) 14.0 mm (0.5512 in.)
Piston pin diameter (service limit) 13.97 mm (0.5500 in.)