Sierra 25W-40 4-Stroke Catalyst Marine OilThis Sierra Premium Blend Engine Oil meets modern recreational 4-stroke engines with or without emission catalyst systems. Sierra 25W-40 is approved for all 4-stroke applications including outboard, sterndrive, and inboard.Features:Exceeds all 4-stroke requirements including FC-W and FC-W Cat CompatibleFormulated to offer maximum corrosion protectionAdvanced lubrication for extended engine life and wear protection”ZDDP” anti-wear additive technologyPrevents phosphorus depletion and extends the emission catalyst lifeNMMA FC-W CertifiedDeveloped for the marine environment and will out perform standard 4-cycle automotive engine oilsOffers excellent detergency, anti-oxidants, antiwear, and corrosion protectionExcellent low temperature operating propertiesHow much oil does my engine need?It varies model to model, check out our Engine Oil Capacity Guide for more information and capacity charts!// Interchangeable with:Mercury Marine:92-8M0078627Frequently Asked QuestionsWhat is Sierra 25W-40 4-Stroke Catalyst Marine Oil used for?Sierra 25W-40 4-Stroke Catalyst Marine Oil is a premium blend engine oil approved for 4-stroke outboard, sterndrive, and inboard applications. It is formulated for modern recreational marine engines with or without emission catalyst systems and provides lubrication, wear protection, and corrosion protection.Is Sierra 25W-40 Catalyst Marine Oil compatible with emission catalyst systems?Yes. Sierra 25W-40 is formulated for modern recreational 4-stroke engines with or without emission catalyst systems. Its formulation helps prevent phosphorus depletion and is designed to extend emission catalyst life.What protection does Sierra 25W-40 4-Stroke Marine Oil provide?Sierra 25W-40 provides corrosion and wear protection through advanced lubrication and ZDDP anti-wear additive technology. It also offers detergency and antioxidant properties and is formulated to support extended engine life in the marine environment.Does Sierra 25W-40 Marine Oil meet FC-W requirements?Yes. Sierra 25W-40 4-Stroke Catalyst Marine Oil is NMMA FC-W Certified and is formulated to exceed 4-stroke requirements, including FC-W and FC-W Catalyst Compatible requirements.Can Sierra 25W-40 Marine Oil be used in outboard, sterndrive, and inboard engines?Yes. The product description states that Sierra 25W-40 is approved for all 4-stroke applications, including outboard, sterndrive, and inboard engines. Verify the oil requirements for your specific engine before use.What marine oil is Sierra 25W-40 4-Stroke Catalyst Marine Oil interchangeable with?Sierra 25W-40 4-Stroke Catalyst Marine Oil is listed as interchangeable with Mercury Marine part number 92-8M0078627. Verify the required oil specification for your specific application before use.//