{"product_id":"sierra-9555cat4-5w30-semi-synthetic-catalyst-inboard-engine-oil-5qt","title":"Sierra 9555CAT4 5W-30 Semi-Synthetic Catalyst-Compatible Inboard Engine Oil — 5 Qt","description":"\u003ch2\u003eSemi-Synthetic 5W-30 Engine Oil for Non-Turbo Inboard Marine Engines\u003c\/h2\u003e\u003cp\u003eSierra 9555CAT4 is a semi-synthetic 5W-30 engine oil engineered for non-turbo inboard marine engines equipped with catalytic converters. Built on premium base stocks with an industry-leading additive system, it meets and exceeds both FC-W Catalyst Compatible and FC-W specifications — as well as API SM category requirements — making it the correct choice for modern inboard engines where catalyst protection matters.\u003c\/p\u003e\u003cp\u003eThe 5-quart size covers a full oil change on most inboard applications in a single container.\u003c\/p\u003e\u003ch3\u003eKey Benefits\u003c\/h3\u003e\u003cul\u003e\n\u003cli\u003eFC-W Catalyst Compatible and FC-W certified — meets API SM requirements\u003c\/li\u003e\n\u003cli\u003eAdvanced ZDDP additive technology prevents phosphorus depletion, protecting catalytic converter life\u003c\/li\u003e\n\u003cli\u003eEnhanced detergent package suspends and prevents sludge buildup\u003c\/li\u003e\n\u003cli\u003eReduces friction to maintain consistent engine performance\u003c\/li\u003e\n\u003cli\u003eResists thermal and oxidation breakdown under extreme operating temperatures\u003c\/li\u003e\n\u003cli\u003eHigh shear stability maintains viscosity and prevents excessive thinning under load\u003c\/li\u003e\n\u003c\/ul\u003e\u003ch3\u003eApplication\u003c\/h3\u003e\u003cp\u003eDesigned for \u003cstrong\u003enon-turbo inboard marine engines\u003c\/strong\u003e equipped with catalytic converters. Confirm your engine manufacturer’s viscosity and catalyst-compatible oil specification before use.\u003c\/p\u003e\u003ch3\u003eParts Desk Insights\u003c\/h3\u003e\u003cp\u003eThis is the right oil for customers with modern non-turbo inboard engines — particularly those with MerCruiser or similar catalyst-equipped systems where using a non-catalyst-compatible oil can damage the converter over time. Best use case: annual or seasonal oil changes on catalyst-equipped inboard engines where the manufacturer specifies a 5W-30 FC-W Catalyst Compatible oil. The 5-quart size is a natural fit for a single full-change, which makes it easy to sell as a complete service item. Always verify the engine’s catalyst compatibility requirement — not all inboards need this spec, but those that do should never run without it.\u003c\/p\u003e","brand":"LNS","offers":[{"title":"Default Title","offer_id":51199654887460,"sku":"47-9555CAT4","price":104.19,"currency_code":"CAD","in_stock":false}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0743\/5799\/7604\/files\/47-9555CAT4.jpg?v=1785611217","url":"https:\/\/marisolmarine.com\/products\/sierra-9555cat4-5w30-semi-synthetic-catalyst-inboard-engine-oil-5qt","provider":"Marisol Marine Company","version":"1.0","type":"link"}