Bushing Seal Kit for Mercruiser R MR Alpha One 23-805041A2 New and Re-Designed Shift Shaft Bushing and Seal Kit for a Mercruiser Sterndrive. Replaces the small weak seal used originally on the shaft that runs through the exhaust portion of the gimbal housing. It fits Models; MC-1/R/MR/Alpha One & Alpha One Gen II, Serial No. Range F094774 & Below. This item replaces 23-805041A2.