My 97' Mariner 25hp 2-stroke is stamped by mercury marine and has same block, controls, lowerunit, parts, and propellers made the same as 25hp mercury 2-strokes.I believe Mariner was a Yamaha/Mercury partnership created to compete with Johnson/Evinrude's multiple brand marketing. I believe Yamaha made the 25 HP motors. Have you checked to see what manufacture's parts your motor is compatible with? I had a late 80' Mariner 30 with yamaha 25 stickers. I put the Yamaha sticker pack on it to freshen it up. This made sense because the block was stamped with the Yamaha logo and all of the parts were exactly the same as the same year Yamhaha motor.