My sister has a 2005 montauk with the carb 4 stroke and its in the shop every two months on the spot with fuel system problems. Mercury's answer: poor design, was corrected on the new EFI model. Purchase and EFI model.
the kicker, boston whaler has to hold up the warranty, not mercury, and whaler is being a pain in the azz.
I'm sorry i recommended boston whalers to her and her husband. Great boat, not great customer service. (unless you buy a bigger boat)