Sierra FC-W 10W-40 4-Stroke Semi Synthetic Marine OilSierra 10W-40 FC-W 4 Stroke engine oil is a semi synthetic blend that has been formulated to provide superior protection for outboard engines. The proprietary blend of conventional with synthetic lubricants allow this oil to keep your engine running smoothly under high loads and running stresses.*Do NOT mix with gas. Not for use in 2 cycle pre-mix, injected engines, inboards/sterndrives equipped with catalytic converters How much oil does my engine need?It varies model to model, check out our Engine Oil Capacity Guide for more information and capacity charts!// Benefits of Using Sierra FC-W 10W-40 Semi-Synthetic Engine Oil Semi Synthetic blend; Direct Suzuki replacement oil; Superior protection; NMMA FC-W certified/API-SL; Sold in Quart & gallon quantities; Sierra 10W-40 FC-W Engine Oil Interchange18-9551-2 - Quart Suzuki Outboard; 990C0-01E30-QUA; 990C0-10W40-1QT; 18-9551-3 - Gallon Suzuki Outboard; 990C0-01E30-GLN; 990C0-10W40-1GL;