Sierra 18-9410-2: Sierra 94102 30 Wt. Full Synthetic 4-Cycle Marine Engine Oil, Qt.A special blend of synthetic base oil and a balanced additive system that exceeds the FC-W requirements for marine engine oil.Recommended for gasoline and diesel inboard and sterndrive enginesSuperior engine protection during startups, operation and storageReduces friction and wear for extended engine lifeReduces oil consumption and improves fuel economy..