38580-ZY3-003 Main Relay Assembly - Overview. The 38580-ZY3-003 Main Relay Assembly is a critical electrical component designed for Honda marine engine systems. This OEM relay acts as a switch to manage the flow of electrical power to various engine subsystems, supporting the starting and running functions of the engine. By ensuring proper electrical distribution, it plays a vital role in maintaining the reliable operation and consistency of your Honda marine engine. Designed with exact factory