Lower Shift Shaft 815919A1 is the OEM replacement part for MerCruiser Alpha Gen II gearcases, used to translate the external shift lever input into gear engagement inside the lower unit. Listed in MerCruiser catalogs and by marine parts retailers as 815919A1, this shaft is a component of the gearcase shift mechanism that enables forward and reverse selection. It is associated with 1991‑and‑later Alpha Gen II drives and is commonly sold by reputable marine suppliers as a direct replacement for worn or damaged shift shafts. When replacing, verify compatibility with your specific MerCruiser Alpha Gen II model and year to ensure proper fit and operation.
