Outboard Fuel Filter | Sierra 18-7979 Sierra Outboard Fuel Filter | Sierra 18-7979 Replacement cartridge fuel filter element for various Mercury & Yamaha 4-stroke outboards. Sierra cartridge fuel filter element Fits various Mercury, Mariner & Yamaha 4-stroke outboards Replaces Mercury 35-881540 Replaces Yamaha 68V-24563-00-00