Yamalube® 4W 10W-40 for Sport Boat and Watercraft Specifically approved for use with Yamaha high-performance 4-Stroke Marine Watercraft engines found in WaveRunners® and Yamaha Sport Boats. Heavily fortified with detergents, anti-wear and corrosion additives to protect in the harsh marine environment. Designed for the needs of 4-Stroke WaveRunners® and Sport Boats. Factory Engineered: Approved by the same Yamaha team responsible for the design and engineering of WaveRunner and Sport Boat engines, this oil will provide the anti-corrosion and anti-wear performance demanded by products in a marine environment. When it comes to performance and protection, there is only one choice-Yamalube.