Mercury Seal O-Ring - 25-8M0067212. The Mercury Seal O-Ring 25-8M0067212 is a genuine OEM replacement component designed to ensure a secure, leak-resistant seal within your marine engine system. Built for precision and reliability, this O-ring helps maintain proper pressure and fluid retention, protecting internal engine components from contamination and performance issues.. Key Features. OEM Quality Assurance - Manufactured to Mercury Marine's exacting specifications. Durable Elastomer Construc