Yamaha - Adaptor Engine Connection Component 6H4-15787-01-00. Overview. Adaptors are one of those parts you don't think about until something doesn't line up or seal the way it should. I've run into situations where a worn or damaged adaptor caused small issues that turned into bigger headaches over time. It's there to make sure components connect cleanly and function as a unit. When it's right, everything fits the way Yamaha intended and runs without issues.. Key Features. Component Interface Support - Connects key engine parts to ensure proper alignment and function.. Secure Fitment Design - Helps maintain tight, reliable connections between components.. OEM Precision Build - Manufactured to Yamaha specifications for accurate fit and performance.. Durable Construction - Designed to withstand heat, vibration, and marine conditions.. System Stability Support - Helps prevent misalignment and maintain consistent operation.. Engine & Boat Compatibility. Designed for Yamaha outboards with