http://www.ppc.au.com/access_lanox2d.htm
Old man has used Inox on his 1998 outboard and trailer since new with no ill effects, the manufacturer warns inox "may" affect natural rubber but I don't know how much natural rubber is still used in outboard plumbing? I've heard the same regarding wiring insulation going hard but after a number of years it goes hard anyway so may just be age to blame not the inox.
I will take it off your hands free of charge if you are going to dump it.. save you paying disposal fees