Yamaha O-Ring 93210-33M85-00. Overview. The Yamaha 93210-33M85-00 O-Ring is a genuine OEM sealing component designed to maintain proper sealing within select Yamaha outboard engine assemblies. O-rings play an essential role in preventing leaks by creating a tight seal between connected engine components.. Over time, O-rings can become brittle, flattened, or damaged due to heat, pressure, and fuel or oil exposure. Replacing worn O-rings helps maintain proper sealing performance and prevents leaks