31630-ZY3-013 Alternator Assembly - Overview. The 31630-ZY3-013 Alternator Assembly is a vital component of Honda marine engine systems. This high-quality alternator produces electrical power necessary for charging the battery and running onboard electrical systems, ensuring your marine engine operates reliably. Designed to fit seamlessly within Honda's Active Marine engines, it guarantees perfect compatibility and optimum performance.. Key Features. 12-volt, 90-amp alternator with clockwise rot