Mercury - Threaded Hose Barb Fuel Line Fitting Brass Construction Part Number 89771Q2. Overview. When it comes to your fuel system, the little connections matter just as much as the big components. A threaded hose barb may not be the most glamorous part on your boat, but when it's built right, you feel the difference in every clean start and every steady run. The Quicksilver 89771Q2 Threaded Hose Barb gives you that sense of security - the kind that comes from knowing your fuel line is tight, we