#4 Male Flare Plug

The #4 Male Flare Plug is a precision hydraulic fitting engineered for marine fuel and coolant systems where reliability under pressure is non-negotiable. Designed for boaters and marine mechanics who demand leak-free connections in demanding saltwater and freshwater environments, this aluminum flare plug seals threaded ports with confidence. Whether you're maintaining an inboard engine, fuel distribution manifold, or cooling circuit on a center console, pontoon, or cabin cruiser, this fitting ensures your vessel stays watertight and operational through seasons of hard use.

Constructed from lightweight aluminum and finished in protective red anodizing, the #4 Male Flare Plug resists corrosion from marine environments while maintaining durability. The flare fitting design creates a metal-to-metal seal that tightens as pressure increases, eliminating the need for tape or sealant compounds that degrade in fuel or coolant applications. The hex head design allows for controlled torque application using standard wrenches, preventing overtightening that can damage threads or undertightening that invites seepage. At just 0.03 lbs, this compact component integrates seamlessly into tight engine compartments without adding weight to your vessel.

Marine technicians and DIY boaters benefit most from stocking this fitting for emergency repairs, system modifications, or preventive maintenance on any vessel using AN (Army-Navy) standard hydraulic systems. The #4 AN specification delivers compatibility with common fuel line and coolant hose assemblies found across outboard, inboard, and sterndrive platforms. Installation is straightforward: insert into the female port and tighten with a wrench until snug—no special tools or expertise required. Keeping spare flare plugs onboard ensures you can cap off disconnected lines during winterization, repairs, or component swaps without risk of contamination or fluid loss.