"I have a 3.0 Merc I/O in an old boat now, I'm looking around for a new boat and believe I want an outboard, but I really like the layout of the I/O 185, especially the swim platform. So I was just curious to see what the bigger engine may entail... "
you answered your own ?.. maintenance of an outboard is simpler than an inboard/outboard.. period, end of story....more things can go wrong with an inboard/outboard, ie- if your bilge stops working or is clogged, can result in swamping your engine.. obviously with an outboard that wont happen ever... unless you sink the boat... stick with your instincts here,, get an outboard motor, you might end up spending a bit more for it, but worth it