Sierra 18-7718 Mercury Fuel Filter Sierra Inline Fuel Filters are direct replacement OEM filters, making them easy to install. All Sierra Inline fuel filters are tested and approved for ethanol-based fuels and meet the demands of todays high tech-high performance engines. In-line, under cowl fuel filter Sonically sealed end caps. OEM matched filter media. Maximum performance with no restrictions. Approved for use with ethanol-based fuels. It is recommended that you inspect filters regularly and