Mercury Mariner 25HP 4-Stroke Outboard Service Manual 1997, Page 155Get this manual
Oil Filter, Thermostat, and Exhaust Cover Removal 1Remove oil filter by turning counterclockwise as shown
3Remove exhaust cover boltsSeparate exhau st cover and gasket from cylinder block
a ",(aBolts (7)Exhaust Cover
cGasket
55854 Oil Filter
Cylinder Head Removal
1Refer to Section 4A for cylinder head removal