90303-GC2-630 Nut (5mm) - Overview. The 90303-GC2-630 Nut (5mm) is a critical OEM component used in Honda marine engine systems. This genuine Honda flange cap nut serves as a fastener that ensures secure connections within the engine assembly, helping to maintain mechanical integrity and reliable operation. Designed to exact factory specifications, this nut guarantees seamless integration with existing parts, maintaining optimal performance and durability.. Key Features. Genuine Honda OEM 5mm Nut, Flange Cap designed for marine applications.. Ensures secure fastening of components within the marine engine system.. Meets Honda factory specifications for dimensions and tolerances.. Provides reliable mechanical connection critical for engine operation.. Designed to integrate cleanly with accompanying hardware and seals.. Maintains expected durability, performance, and operational feel with OEM-style design.. Why Choose Genuine OEM. Using original Honda parts like the 90303-GC2-630 Nut (5m