Sierra Marine 18-9410-4 Full Synthetic SAE 30 4-Stroke Marine Engine Oil – FC-W Certified (5 Quart Jug)

Sierra 18-9410-4 is a 100% full-synthetic SAE 30 marine engine oil engineered for today’s high-performance 4-stroke gasoline and diesel inboard, sterndrive, and outboard engines. Its advanced synthetic base stocks and additive package exceed NMMA FC-W requirements, providing unmatched protection against wear, corrosion, and thermal breakdown in the harshest marine environments.

Ideal when your engine calls for a straight SAE 30 FC-W oil (Yamaha, Honda, Suzuki, some Mercury/MerCruiser, Yanmar diesel, etc.).

Key Features & Benefits

• 100% Full Synthetic — superior performance and longer life than mineral or blends
• NMMA FC-W Certified + meets/exceeds API CF & SL
• Recommended for both gasoline and diesel 4-stroke marine engines
• Outstanding wear protection during cold starts and high-RPM operation
• Excellent corrosion resistance — perfect for saltwater use and seasonal storage
• Reduces friction and oil consumption while improving fuel economy
• Superior thermal/oxidation stability — stays in grade longer, keeps engines cleaner
• High detergency prevents sludge and varnish buildup

Specifications

• Viscosity: SAE 30 (straight grade)
• Type: 100% Full Synthetic
• Volume: 5 U.S. Quarts (4.73 L / ~1.25 gallons) in a convenient jug with pour spout
• Certifications: NMMA FC-W, API CF/SL
• Sold as: Single 5-quart jug
• Approximate shipping weight: 10.8–11 lbs (same as the 25W-40 5 qt jugs)

Common applications:

• Yamaha 4-stroke outboards specifying SAE 30
• Honda, Suzuki, Tohatsu, and many marine diesels calling for SAE 30 FC-W
• Any 4-stroke marine engine recommending full-synthetic straight-30 weight

(No manufacturer warranty — see Sierra’s standard terms)