Sierra 18-1705 Alpha Gimbal Housing Hinge Pin Replaces 77123This Sierra gimbal housing hinge pin is designed for use with MerCruiser Alpha Gen I & II drives with a grease port.Fits: MerCruiser Alpha One Gen I drives from 1983-1991 with serial numbers 06225577 thru 0D469858; MerCruiser Alpha One Gen II drives from 1990-Present with serial numbers 0D469859 & Up; Interchangeable with: Mallory; 9-73130; MerCruiser Stern Drive; 77123A1; 65547; 77123;