Mercury - Quicksilver 816856Q3 Quick Disconnect Fuel Line Connector 5/16-Inch Hose Mercury & Mariner Outboards 816856Q3. Overview. Few things are more frustrating than fighting a leaky or loose fuel line when you're ready to head out. The Quicksilver 816856Q3 Quick Disconnect Fuel Line Connector fixes that for good. Designed for Mercury and Mariner outboards, it provides a tight, secure clip-on connection between your engine and a 5/16-inch (8mm) fuel line.. It's made from tough, marine-grade ma