Sierra Marine 18-9420-3 Premium Blend 4-Stroke Marine Engine Oil – 10W-30 FC-W Certified (1 Gallon Jug)

Sierra 18-9420-3 is the exact same ultra-popular Premium Blend 10W-30 4-stroke marine oil that boaters love (same formula as the quart 18-9420-2), now in a convenient 1-gallon jug with built-in pour spout. NMMA FC-W certified and specifically engineered for modern 4-stroke outboards, sterndrives, and inboards running in fresh or saltwater.

This is the #1 go-to oil for almost all newer Yamaha, Mercury (75 hp+), Honda, Suzuki, Tohatsu, and Evinrude/Johnson 4-strokes that specify 10W-30 FC-W.

Key Features & Benefits

• NMMA FC-W Certified + meets API SJ / CF-2 / CH-4
• Excellent cold-start flow (10W) with high-temperature protection (30 weight)
• Superior corrosion protection — perfect for seasonal storage and saltwater environments
• High detergency keeps pistons clean and prevents ring sticking
• Advanced anti-wear additives for heavy-load, high-RPM marine use
• Outperforms regular automotive 10W-30 in marine conditions
• Backed by Sierra’s 50+ years as the marine aftermarket leader

Specifications

• Viscosity: SAE 10W-30
• Type: Premium Blend (semi-synthetic)
• Volume: 1 U.S. Gallon (3.785 L) jug with handle and pour spout
• Certifications: NMMA FC-W, API SJ, CF-2, CH-4
• Sold as: Single 1-gallon jug
• Approximate shipping weight: 8.4–8.8 lbs (most shippers list it at 9 lbs)

Common applications:

• Yamaha 4-strokes (F70 and larger, most current models)
• Mercury 75–400 hp 4-strokes
• Honda, Suzuki, Tohatsu/Nissan specifying 10W-30 FC-W
• Many gasoline sterndrive/inboard engines calling for 10W-30

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