Yamaha - Oil Tank Sub Assembly Oil Storage Component 6K1-21708-03-00. Overview. The Yamaha Oil Tank Sub Assembly 6K1-21708-03-00 is one of those parts you don't think about until your oil system starts acting up. It holds and feeds oil to the engine, so when it's not working right, you risk running lean on lubrication-and that's not something you want to gamble with. Whether you're seeing warning lights or inconsistent oil delivery, this is a key component to check. Keeping it in good shape means your engine stays protected every time you're out on the water.. Key Features. • Reliable Oil Storage - Holds engine oil securely for consistent delivery to the system.. • Steady Oil Feed Support - Helps maintain proper lubrication flow during operation.. • OEM Fit Design - Matches Yamaha specifications for proper installation and function.. • Durable Marine Build - Designed to withstand vibration, heat, and harsh conditions.. Compatibility. Compatible with select Yamaha outboard engines using