17371-ZY9-000 Muffler Case - Overview. The 17371-ZY9-000 Muffler Case is a crucial component of Honda marine engine systems, specifically supporting the exhaust system. It acts as the protective outer shell for the muffler, effectively dampening sound and directing exhaust gases safely. Engineered to exact specifications, it ensures seamless integration with existing parts, maintaining optimal performance and durability.. Key Features. Designed as a protective casing for the muffler, contributin