Before you order, identify your drive.
MerCruiser produced several sterndrive models before the Alpha One, including the R, 888, 898, I, and MR. The Alpha One introduced changes to the direction of the lower gear cuts and the bearing load design on the lower driveshaft, providing more stable pinion gear clearance for added strength.
Identifying the unit is an important first step. Your serial number, model year, and physical drive details help us narrow down the correct parts.
Plan your repair with a service manual.
Rebuilding or repairing a sterndrive can be difficult. A factory service manual explains procedures and lists the special tools a job may require. Manuals are useful even when a technician performs the work, helping you understand the repair.