4 Stroke Boat Oil

Sierra's 4 stroke boat oil is engineered to protect and extend the life of today’s inboard, outboard & sterndrive engines while meeting the demands of marine operating conditions. Our synthetic, premium, and direct injection oils are designed to meet or exceed OEM standards in a range of motors, including Mercury, Yamaha, Suzuki, Volvo, Nissan, and Yamaha. Shop Sierra's full line of boat engine oils, or use our parts-finder tool to search the extensive Sierra catalog. Backed by the best warranty in the marine industry, Sierra oil will keep you running safe and smooth all season.