Industrial 55989A8 Acorn Anode and Bolt Assembly

55989A8 Acorn Anode Bolt Kit is an anodic bolt assembly designed for MerCruiser Sterndrive gimbal housings (R, MR, Alpha One) in the 1983–1990 model years. This Genuine Mercury Marine part provides sacrificial anodic hardware at the gimbal housing-to-transom interface, helping to protect stern drive components from galvanic corrosion in salt and freshwater environments. The part is identified in Mercury/MerCruiser catalogs as BOLT ASSEMBLY, ANODIC (55989A8) and is listed alongside related items such as the Anode Kit, Bolt (55989Q9) and corresponding anodic washers used with the gimbal housing assembly. When servicing or replacing worn anodic hardware on these sterndrive configurations, this anodic bolt assembly supports the overall corrosion-protection system for the gimbal housing, ensuring continued protection for the transom connection and related mounting hardware on MerCruiser R/MR/Alpha One drives from that era.