Mercury Mariner 4 and 5HP 4-Stroke Outboards Service Shop Manual 1999, Page 19Get this manual
MAINTENANCE
Changing Engine Oil
ENGINE OIL CAPACITY 15 fI oz (450 mL) OIL CHANGING PROCEDURE 1Place outboard in an upright slightly tilted position2Turn the steering on the outboard to gain access to the drain plug (a) Remove drain plug and drain engine oi into an appropriate containerLubricate the seal on the drain plug with oil and reinstall