91251-ZY6-003 seal (23x36x8) - Overview. The 91251-ZY6-003 seal (23x36x8) is a critical component in Honda marine engine systems, specifically designed for sealing water passages with dimensions of 23mm diameter, 36mm outer diameter, and 8mm thickness. This OEM water seal ensures proper sealing within the lower unit or gear case, preventing water ingress that could damage internal engine parts. By maintaining a tight seal, it supports reliable engine operation and prevents costly repairs due to