Genuine Mariner Oils and Grease are available by mail order. Mariner / Quicksilver branded outboard oils are the genuine OEM product, formulated to withstand the harsh environment in which Mariner outboards engines operate. Mariner oil filters and the oil should be changed at the end of each season, as should the gearbox oil. The leg oil should be changed by using Premium Plus gear lube.
Genuine Mariner Quicksilver branded oils are the genuine OEM fitment and should always be used to ensure the safe and correct use of your outboard. Smaller outboards generally use 10w 30 and medium outboards use either 25w40 or 10w30.