Engine Mount Rear Mercruiser | Sierra 18-2193 Mercruiser Rear Engine Mount Mercruiser rear engine mount Replaces Mercruiser 99297A1 For 120/140 HP s/n 6229717 and up For all 224 CID blocks For all 898, 200, 228, 230, 260, 300, and 320 HP For all 350-454 Magnums