91406-ZVT-000 Drain Tube - Overview. The 91406-ZVT-000 Drain Tube is a critical component in Honda marine engine systems, specifically designed to facilitate the controlled evacuation of water or fluids from key engine components. This drain tube supports fluid flow management within the marine engine system, ensuring reliable operation and preventing fluid accumulation that could impair performance.. Key Features. Designed as an original equipment manufacturer (OEM) Honda marine engine part to