Mercury - 816296A3 Fuel Filter Kit 5-15HP Carbureted FourStroke Outboards Inline Filter & Hoses 816296A3. Overview. Even small outboards need clean fuel to perform their best. The Mercury 816296A3 Fuel Filter Kit helps keep your 5-15HP carbureted FourStroke outboard running smooth by trapping moisture and debris before they reach the engine. A dirty or clogged filter can rob power, foul plugs, and shorten engine life - this simple kit protects against all that with an easy-to-install OEM setup..