{"product_id":"sierra-fuel-filter-21-micron-medium-1-12-thread-spin-on-replacement-for-marine-engines","title":"Sierra Fuel Filter 21-Micron Medium (1\"-12 Thread) Spin-On Replacement for Marine Engines","description":"\u003cp\u003e\u003cstrong\u003eSierra International 18-7846 is a medium, 21-micron replacement fuel filter with 1\"-12 thread designed to fit a wide range of marine and sterndrive engines.\u003c\/strong\u003e\u003c\/p\u003e\n\n\u003cp\u003eThis replacement fuel filter is engineered to match the fit and filtration performance of common OEM items including OMC 502905, CRUSADER 98041, OMC 174144, and VOLVO 3851218-2. With a 21-micron rating and standard 1\"-12 thread pitch, the part serves as a universal-fit service item for many sterndrive and inboard\/outboard systems. Sierra backs the part with its customer satisfaction warranty and provides an alternative to manufacturer-specific cartridges for routine maintenance and repairs.\u003c\/p\u003e\n\n\u003ch3\u003eHow does the 21-micron rating affect fuel cleanliness?\u003c\/h3\u003e\n\n\u003cp\u003eA 21-micron filter captures medium-sized particulates that can harm fuel system components without restricting flow excessively. It balances filtration and engine performance, helping to keep injectors, carburetors, and pump components freer of abrasive debris.\u003c\/p\u003e\n\u003cul\u003e\n  \u003cli\u003eRated to remove particles down to 21 microns in size\u003c\/li\u003e\n  \u003cli\u003eDesigned to reduce contaminant build-up in fuel pumps and injectors\u003c\/li\u003e\n  \u003cli\u003eMaintains adequate fuel flow for typical marine engine demands\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003eWill this replace my OEM filter (which models does it fit)?\u003c\/h3\u003e\n\n\u003cp\u003eThe Sierra 18-7846 is a direct-style replacement for several OEM part numbers and is built to match their thread and filtration specifications. It is compatible with OMC and Volvo part references and fits many Crusader applications when the listed OEM numbers correspond to your existing filter.\u003c\/p\u003e\n\u003cul\u003e\n  \u003cli\u003eCross-references: OMC 502905, OMC 174144, CRUSADER 98041\u003c\/li\u003e\n  \u003cli\u003eAlso compatible with VOLVO 3851218-2 where a 21-micron, 1\"-12 thread is required\u003c\/li\u003e\n  \u003cli\u003eUniversal-fit design simplifies aftermarket replacements\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003eHow do I install and maintain this filter?\u003c\/h3\u003e\n\n\u003cp\u003eInstallation follows the same steps as most spin-on fuel filters: drain or relieve fuel pressure, unscrew the old filter, apply a light oil film to the new filter gasket, and hand-tighten. Replace at regular service intervals or whenever contamination or water in fuel is suspected.\u003c\/p\u003e\n\u003cul\u003e\n  \u003cli\u003eThread pitch: 1\"-12 — confirm thread compatibility with your mounting base\u003c\/li\u003e\n  \u003cli\u003eHand-tighten and follow engine manufacturer torque guidance if available\u003c\/li\u003e\n  \u003cli\u003eInspect for leaks after startup and replace if damaged or clogged\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003eWhat warranty and support does Sierra provide?\u003c\/h3\u003e\n\n\u003cp\u003eSierra covers this part under its customer satisfaction warranty, reflecting the company's support for aftermarket marine replacement parts. Warranty specifics follow Sierra's terms, and support is available for installation or fitment questions.\u003c\/p\u003e\n\u003cul\u003e\n  \u003cli\u003eIncluded in Sierra's industry-standard customer satisfaction warranty\u003c\/li\u003e\n  \u003cli\u003eTechnical help available for fit and cross-reference inquiries\u003c\/li\u003e\n  \u003cli\u003eReplacement or return policies handled per Sierra's warranty terms\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003cp\u003eWho this product is for: Boat owners, mechanics, and marine service shops looking for a reliable, medium-rated replacement fuel filter that matches OMC, Crusader, and Volvo part references. Choose the Sierra 18-7846 if you need a 21-micron, 1\"-12 thread spin-on filter for routine maintenance, retrofit projects, or to keep older sterndrive and inboard\/outboard fuel systems running cleanly. Always confirm compatibility with your engine's service manual or existing filter part number before ordering.\u003c\/p\u003e\n\u003csection class=\"product-faq-snippet\"\u003e\u003ch3\u003eFAQ\u003c\/h3\u003e\n\u003cdiv class=\"faq-item\"\u003e\n\u003cp class=\"faq-q\"\u003eQ: Is the Sierra 18-7846 the same as OMC 502905?\u003c\/p\u003e\n\u003cp class=\"faq-a\"\u003eA: Yes, the Sierra 18-7846 is a compatible replacement for OMC 502905 and other listed OEM numbers.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"faq-item\"\u003e\n\u003cp class=\"faq-q\"\u003eQ: What size particles does this filter remove?\u003c\/p\u003e\n\u003cp class=\"faq-a\"\u003eA: This filter is rated at 21 microns, capturing medium-sized contaminants while maintaining fuel flow.\u003c\/p\u003e\n\u003c\/div\u003e\u003c\/section\u003e","brand":"Sierra","offers":[{"title":"Default Title","offer_id":55162948288855,"sku":"B0001CLG32","price":31.55,"currency_code":"GBP","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/1050\/1524\/7191\/files\/sierra-18-7846-front-view.jpg?v=1790340058","url":"https:\/\/britishgarage.co.uk\/products\/sierra-fuel-filter-21-micron-medium-1-12-thread-spin-on-replacement-for-marine-engines","provider":"British Garage","version":"1.0","type":"link"}