Mercury Mariner 4, 5, and 6HP 4-Stroke Factory Service Manual, Page 20Get this manual
MAINTENANCE
Changing Engine Oil
ENGINE OIL CAPACITY 15 fl 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 plugRemove drain plug and drain engine oil into an appropriate containerLubricate the seal on the drain plug with oil and reinstall