87121-ZV4-A00 Rr (15) Mark - Overview. The 87121-ZV4-A00 Rr (15) Mark is a genuine OEM label used in Honda marine engine systems. This mark serves as a crucial identification decal applied on the rear section of the engine to indicate manufacturing or revision details. It supports the overall system by providing clear labeling that assists in proper servicing, maintenance, and ensuring compliance with factory standards. Designed specifically for Honda outboard engines, it ensures seamless integr