17371-ZY9-H00 Muffler Case - Overview. The 17371-ZY9-H00 Muffler Case is a crucial component within Honda marine engine systems. It serves as a protective housing for the muffler assembly, playing an essential role in noise reduction and safeguarding the exhaust system from environmental damage. Designed to seamlessly integrate with existing parts, this OEM muffler case helps maintain optimal performance and durability of your marine engine equipment.. Key Features. Specifically designed as a mu