Mercury - Storage Seal Fogging Oil Engine Care Series Protective Spray Formula 858081K03. Overview. Every boater knows the mixed feeling that comes when it's time to put the boat away for the season. You turn the key one last time, listen to the engine settle, and hope everything wakes up just as strong months later. Mercury Storage Seal Fogging Oil gives you that peace of mind. It lays down a thick protective coat inside the engine, shielding the metal surfaces you never see but rely on every s