Yamalube 10W30 Marine Full Synthetic Oil (1 Gallon) - QBL-10W30-FS-04. Yamalube 10W30 Marine Full Synthetic Oil is engineered specifically for Yamaha four-stroke outboards operating in demanding marine environments. This full synthetic formula delivers stable lubrication under sustained RPM, heavy prop loads, and high engine temperatures while providing added corrosion resistance against moisture and salt exposure.. Key Features. Viscosity: 10W-30. Type: Marine full synthetic engine oil. Designed for Yamaha four-stroke outboards. Helps protect against wear during high RPM operation. Supports thermal stability to resist breakdown in hot conditions. Marine-focused corrosion protection for storage and downtime. Helps reduce sludge and internal deposits. Size: 1 gallon. OEM Part Number: QBL-10W30-FS-04. Yamalube 10W-30 full synthetic is recommended for use on all outboard engines running 10W-30 engine oil. Performance Benefits. Outboard engines operate differently than automotive engines.