Purpose and Specifications

MOTUL OUTBOARD TECH 4T 10W40 is a semi-synthetic marine engine oil engineered specifically for 4-stroke outboard and inboard gasoline engines. This oil meets the NMMA FC-W certification standard, which ensures compatibility with modern marine engines and their emission control systems.

The 10W40 viscosity rating means the oil flows easily in cold water conditions (down to -20°C) while maintaining a protective film at high operating temperatures (up to +130°C). This dual-temperature performance is critical for marine engines that experience rapid temperature swings.

• Semi-synthetic formulation – Blends mineral and synthetic base stocks for superior protection without the premium cost of full synthetics
• High HTHS viscosity – Maintains a strong protective oil film under extreme heat and engine stress
• Anti-corrosion protection – Specially formulated to resist saltwater and seawater corrosion, a major concern in marine environments
• Shear resistance – Keeps the oil performing consistently even under high-temperature, high-stress conditions
• 1-liter bottle – Convenient size for routine oil checks and top-ups between service intervals

When to Use / Replace?

Replace your outboard engine oil every 100 operating hours or once per season (whichever comes first), or follow your engine manufacturer's specific recommendations. For recreational boaters using their engines 50–100 hours per year, this typically means an annual oil change in spring before the boating season.

Use this oil immediately if your engine manual specifies NMMA FC-W certification or if your manufacturer recommends a 10W40 viscosity. Always check your owner's manual for the exact oil grade and capacity required.

Storage: Keep unopened bottles in a cool, dry place. Properly sealed oil maintains its quality for several years. Once opened, use within the current season to ensure optimal protection.

Frequently Asked Questions

Q: Can I use this oil in both saltwater and freshwater engines?
A: Yes. The anti-corrosion additives protect against both saltwater and freshwater environments, making it suitable for any 4-stroke outboard or inboard engine.

Q: What does the '10W40' rating mean for my boat?
A: The '10W' means it flows easily when your engine is cold (important for winter storage or cold-water boating), and '40' means it stays thick enough to protect at high temperatures. This range covers most boating conditions from -20°C to +130°C.

Q: Is semi-synthetic better than conventional oil for marine engines?
A: Semi-synthetic offers better protection against corrosion and heat than conventional mineral oil, while costing less than full synthetic. For marine engines exposed to saltwater and temperature extremes, it's the practical choice for most boat owners.