Mercury - Fuel Line Connector Fuel System Component Bayonet-Style Brass Fitting 30185T3. Overview. Keeping steady fuel delivery is crucial for older outboards, and the Mercury Marine 30185T3 Fuel Line Connector is made to do exactly that. Designed for Mercury and Mariner TwoStroke outboards built in 1971 and earlier, this bayonet-style connector provides a snug, leak-free fit between your fuel tank hose and the engine. It locks in firmly, holds under vibration, and keeps fuel flowing evenly so y