91351-740-003 O-Ring (41.7X3.5) - Overview. The 91351-740-003 O-Ring (41.7X3.5) is a vital sealing component designed for the Honda marine engine systems. It serves to prevent fluid leaks by creating a secure seal between connected parts, contributing to the efficient and reliable performance of your marine engine. Manufactured to exact factory specifications, this O-ring measures 41.7 mm in outer diameter and 3.5 mm in thickness, ensuring seamless integration with existing parts, maintaining op