87121-ZY5-C00 Rr (135) Mark - Overview. The 87121-ZY5-C00 Rr (135) Mark is a genuine Honda OEM part integral to marine engine systems, specifically designed for Honda outboard motors around the 135 horsepower range. As part of the marking system, this component plays a vital role in clear identification and support of key operational parameters, ensuring seamless integration with existing parts, maintaining optimal performance and durability.. Key Features. OEM Mark Rear (135) provides precise i