Sierra 18-7906-2 4-Cycle Outboard Oil Filter for Mercury, Yamaha Sierra Oil Filters are designed to match your boats OEM Filter and meet or exceed OEM filtration requirements. It is recommended you replace your oil filter after the first initial 20 hours of engine operation. After the first 20 hours, filters should be replaced every 50 hours of operation or at a minimum of once yearly. Features Anti-drain back valves help prevent dry-starts Epoxy coated steel canister prevents corrosion Easy ins