{"product_id":"mercury-4-stroke-synthetic-blend-engine-oil-25w-40-4l-8m0078642","title":"Mercury 4-Stroke Synthetic Blend Engine Oil – 25W-40, 4L | 8M0078642","description":"\u003ch2\u003eMercury 4-Stroke Synthetic Blend Engine Oil – SAE 25W-40, 4L\u003c\/h2\u003e\n\n\u003cp\u003eThe OEM-specified SAE 25W-40 synthetic blend 4-stroke engine oil for Mercury outboard, MerCruiser sterndrive, and Mercury inboard engines, sold in a 4-litre container. The synthetic blend formula delivers improved film strength, better viscosity stability across temperature extremes, and enhanced protection during cold starts and sustained high-load operation compared to conventional marine oil. NMMA FC-W and FC-W Catalyst Compatible certified. Directly supersedes earlier part number 858053KC1.\u003c\/p\u003e\n\n\u003ch3\u003ePart Details\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003ePart Number:\u003c\/strong\u003e 8M0078642\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eOEM Reference:\u003c\/strong\u003e 92-8M0078642\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eBrand:\u003c\/strong\u003e Mercury Marine\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eSupersedes:\u003c\/strong\u003e 858053KC1\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eProduct Type:\u003c\/strong\u003e 4-Stroke Marine Engine Oil – Synthetic Blend\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eViscosity:\u003c\/strong\u003e SAE 25W-40\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eVolume:\u003c\/strong\u003e 4 Litres (approx. 1.06 US gallons)\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eCertification:\u003c\/strong\u003e NMMA FC-W \u0026amp; FC-W Catalyst Compatible\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eSystem:\u003c\/strong\u003e Engine lubrication – crankcase\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003eCompatible Applications\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003eMercury FourStroke outboards requiring 25W-40 crankcase oil (all displacements)\u003c\/li\u003e\n\u003cli\u003eMercury Pro XS FourStroke outboards\u003c\/li\u003e\n\u003cli\u003eMercury Verado FourStroke outboards\u003c\/li\u003e\n\u003cli\u003eMerCruiser sterndrive engines – 3.0L, 4.3L V6, 5.0L V8, 5.7L V8, 6.2L V8, 7.4L V8, 8.2L V8\u003c\/li\u003e\n\u003cli\u003eMercury Marine 4-stroke inboard engines\u003c\/li\u003e\n\u003cli\u003eAny 4-stroke marine engine where SAE 25W-40 synthetic blend is specified — always confirm in your engine owner’s manual\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003eSupersession Note\u003c\/h3\u003e\n\u003cp\u003ePart number 8M0078642 is the current active part number and directly supersedes \u003cstrong\u003e858053KC1\u003c\/strong\u003e. If your parts diagram or service manual references 858053KC1, order 8M0078642.\u003c\/p\u003e\n\n\u003ch3\u003eService Interval\u003c\/h3\u003e\n\u003cp\u003eChange engine oil and filter every \u003cstrong\u003e100 hours or annually\u003c\/strong\u003e, whichever comes first — per the Mercury and MerCruiser service manual. Always replace the oil filter at each oil change. Most Mercury 4-stroke outboards in the 75–200 HP range require 3–4 litres per change; confirm your engine’s capacity in the service manual.\u003c\/p\u003e\n\n\u003ch3\u003eTechnical FAQ\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eWhat’s the difference between this synthetic blend and the conventional 25W-40 (\u003ca href=\"\/products\/mercury-4-stroke-marine-engine-oil-25w-40-4l-part-8m0078640\"\u003e8M0078640\u003c\/a\u003e)?\u003c\/strong\u003e Same viscosity grade, higher-quality base oil. The synthetic blend offers improved film strength, better cold-start protection, and greater viscosity stability under heat compared to the conventional formula.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eIs there a full-synthetic version?\u003c\/strong\u003e Yes — see the \u003ca href=\"\/products\/mercury-4-stroke-full-synthetic-marine-engine-oil-25w-40-1l-8m0078641\"\u003eMercury 25W-40 Full Synthetic 4-Stroke Oil – 1L (8M0078641)\u003c\/a\u003e for the full-synthetic option.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eCan I use automotive 25W-40 instead?\u003c\/strong\u003e No. Automotive oils lack the marine-specific corrosion inhibitors and FC-W certification required for boat engines. Using automotive oil can void your warranty and accelerate internal corrosion.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eMy parts diagram shows 858053KC1 — is this the right replacement?\u003c\/strong\u003e Yes. 8M0078642 directly supersedes 858053KC1.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eWhat if my engine specifies 10W-30?\u003c\/strong\u003e Use the viscosity in your owner’s manual. See the \u003ca href=\"\/products\/mercury-4-stroke-engine-oil-10w-30-4l-part-8m0078638\"\u003eMercury 10W-30 Engine Oil – 4L (8M0078638)\u003c\/a\u003e for that grade.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003eRelated Parts\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003ca href=\"\/products\/mercury-4-stroke-marine-engine-oil-25w-40-4l-part-8m0078640\"\u003eMercury 4-Stroke Engine Oil – 25W-40, 4L (8M0078640)\u003c\/a\u003e — conventional formula\u003c\/li\u003e\n\u003cli\u003e\n\u003ca href=\"\/products\/mercury-4-stroke-marine-engine-oil-25w-40-1l-part-8m0078639\"\u003eMercury 4-Stroke Engine Oil – 25W-40, 1L (8M0078639)\u003c\/a\u003e — 1L synthetic blend\u003c\/li\u003e\n\u003cli\u003e\u003ca href=\"\/products\/mercury-4-stroke-full-synthetic-marine-engine-oil-25w-40-1l-8m0078641\"\u003eMercury 4-Stroke Full Synthetic Engine Oil – 25W-40, 1L (8M0078641)\u003c\/a\u003e\u003c\/li\u003e\n\u003cli\u003e\u003ca href=\"\/products\/mercury-4-stroke-engine-oil-10w-30-1l-part-8m0078637\"\u003eMercury 4-Stroke Engine Oil – 10W-30, 1L (8M0078637)\u003c\/a\u003e\u003c\/li\u003e\n\u003cli\u003e\u003ca href=\"\/products\/mercury-4-stroke-engine-oil-10w-30-4l-part-8m0078638\"\u003eMercury 4-Stroke Engine Oil – 10W-30, 4L (8M0078638)\u003c\/a\u003e\u003c\/li\u003e\n\u003cli\u003e\u003ca href=\"\/products\/mercury-4-stroke-high-performance-engine-oil-25w-50-1-qt-8m0078013\"\u003eMercury 4-Stroke High Performance Engine Oil – 25W-50, 1 Qt (8M0078013)\u003c\/a\u003e\u003c\/li\u003e\n\u003cli\u003e\u003ca href=\"\/products\/mercury-quicksilver-oil-filter-877761k01-75-150-hp-fourstroke-outboard\"\u003eMercury Quicksilver Oil Filter 877761K01 – 75–150 HP FourStroke\u003c\/a\u003e\u003c\/li\u003e\n\u003cli\u003e\u003ca href=\"\/products\/mercury-quicksilver-oil-filter-877769k01-l6-verado-outboard\"\u003eMercury Quicksilver Oil Filter 877769K01 – L6 Verado\u003c\/a\u003e\u003c\/li\u003e\n\u003cli\u003e\u003ca href=\"\/products\/mercury-quicksilver-100-hour-service-kit-8m0094232\"\u003eMercury Quicksilver 100-Hour Service Kit 8M0094232\u003c\/a\u003e\u003c\/li\u003e\n\u003cli\u003e\u003ca href=\"\/products\/mercury-quicksilver-100-hour-service-kit-8m0097854\"\u003eMercury Quicksilver 100-Hour Service Kit 8M0097854\u003c\/a\u003e\u003c\/li\u003e\n\u003cli\u003e\u003ca href=\"\/collections\/mercury-mercruiser-engine-maintenance-parts\"\u003eBrowse all Mercury MerCruiser Engine Maintenance Parts\u003c\/a\u003e\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003chr\u003e\n\n\u003ch3\u003eParts Desk Insights\u003c\/h3\u003e\n\u003cp\u003eThe 4L synthetic blend is the right choice for a complete single-engine oil change on most Mercury 4-stroke outboards and MerCruiser sterndrives that specify 25W-40 — particularly engines in the 75–200 HP range that typically require 3–4 litres per service. The synthetic blend formula is the practical step up for customers who want better protection than conventional oil without the cost of full synthetic: well-suited for saltwater use, high-hour engines, or boats that sit for extended periods between uses.\u003c\/p\u003e\n\u003cp\u003eThe most common customer mistake is selecting oil based on viscosity alone without confirming the correct formula for their engine — Mercury offers conventional, synthetic blend, and full synthetic in 25W-40, and the right choice depends on the engine model and Mercury’s current recommendation for that serial range. Always cross-reference with the Mercury parts diagram and owner’s manual. Always replace the oil filter at the same time as the oil — see the \u003ca href=\"\/products\/mercury-quicksilver-oil-filter-877761k01-75-150-hp-fourstroke-outboard\"\u003e877761K01 filter\u003c\/a\u003e for most 75–150 HP FourStroke outboards.\u003c\/p\u003e","brand":"MERC","offers":[{"title":"Default Title","offer_id":43563912986660,"sku":"8M0078642","price":84.91,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0743\/5799\/7604\/files\/8M0078642.png?v=1771539888","url":"https:\/\/marisolmarine.com\/products\/mercury-4-stroke-synthetic-blend-engine-oil-25w-40-4l-8m0078642","provider":"Marisol Marine Company","version":"1.0","type":"link"}