Universal Aluminum Fuel Hose Fitting - 1/4" NPT x 3/8" Barb - (Anti-Siphon Valve)

The Universal Aluminum Fuel Hose Fitting – 1/4" NPT x 3/8" Barb with Anti-Siphon Valve is essential safety equipment for anyone running a boat with an outboard or inboard fuel system. After decades on the water, fuel line leaks and siphoning incidents represent some of the most dangerous—and avoidable—failures in marine operation. This compact fitting bridges two critical fuel system components while preventing accidental fuel siphon, which can drain your tank when the engine is shut down or if the fuel line ruptures above the tank level.

Built from lightweight aluminum alloy, this Attwood Marine fitting combines durability with corrosion resistance—critical in saltwater and freshwater environments alike. The 1/4" NPT (National Pipe Thread) connection provides a standard, leak-proof sealed male thread interface, while the 3/8" barb end accommodates common fuel hose sizes with a secure slip-fit design. The integrated anti-siphon valve is the key feature: it automatically closes when fuel pressure drops, blocking backflow and preventing fuel from draining through a ruptured or disconnected hose. This passive safety mechanism requires no electrical power and operates reliably across thousands of hours of engine run time.

Any boater upgrading an aging fuel system, replacing damaged fittings, or installing a new fuel line assembly will benefit from this universal design. It's equally suited for portable fuel tanks, engine fuel inlets, or remote fuel filter applications—anywhere you need a compact, anti-siphon junction that meets USCG and ABYC standards for recreational marine use. Installation is straightforward: thread the NPT end into your tank fitting or engine component, then slide the barbed end over matching fuel hose and secure with a stainless-steel hose clamp. Weighing just 1 pound and small enough to fit tight engine compartments, this fitting is a proven upgrade that adds a critical safety layer without complications.