Mercury Mariner V-250 V-275 Outboard Service Shop Manual 1990, Page 109Get this manual
9Disconnect remote oil tank hoses from engine 11 Remove nuts and lockwashersthree each sidefrom base of power headRemove bolt from exhaust adaptor
a-Oil Tank Hose (Inlet)Nut and Lockwasher (3 Each Side)
12Remove wing nuts from ftywheel remove cover