To follow Fr. Frank's post, if you do most of those maintenance hours on the stern drive when you are supposed to you will generally be a happy boater. Guys get themselves into trouble-big trouble sometimes-when they don't perform the big ticket maintenance items. There are a few-the drive bellows, in particular, that require your frequent inspection. I have been very happy with the package-my mercruiser has been very happy for the last three years and as Fr. Frank stated if the ill-fated repower day comes at a bad time-I'm looking at about 6000 for a brand new drop in 250 hp mercruiser engine to replace mine.
Good luck with the choice and feel free to pm me with any specific questions.
