Mercury Mariner 4 and 5HP 4-Stroke Outboards Service Shop Manual 1999, Page 195Get this manual
GEAR HOUSING
Water Pickup Screen
1Remove screw (a) and water pickup screen (b)
Cleaning and Inspection
Gear HousingBearing Carrier Castings
1Thoroughly clean gear housingbearing carrier casti ngsBe sure all old gasket material
is removed from mating surfaces and that carbon deposits have been removed from exhaust passages