Mercury - Quicksilver Anode Corrosion Protection for 25-50HP Outboards 804043. Overview. Salt, moisture, and time can eat away at metal, and that's where the Mercury Marine 804043 Quicksilver Anode earns its keep. This small piece of metal quietly does an important job - it takes on corrosion so your engine doesn't have to. Built for Mercury 25-50HP 2-Stroke Jet, International, and Lightning outboards (2006 and newer), and 25-30HP 4-Stroke EFI 3-cylinder outboards (2022 and newer), it's designed