Ted, I had the same situation last year when I got my first new boat. I
took it to the gas station, filled it up to the brim, spent some time on the
water, and parked it in the garage. I soon noticed gas oders in the garage.
The odor of gas was especially strong in the forward hatches, one for
storage and one for the trolling motor battery.

On my boat, the fill is at the rear of the boat, but the fuel cell runs up
the beam. The dealer suggested it was normal evaporation trapped by the
cover. The problem was I had the boat in the garage uncovered.

The dealer took the boat back in the shop, conducted a pressure check (no
leaks), took the deck off to check fittings (no leaks), and had a number of
techs look over the fuel system (still no leaks). I got the boat back on
the water and it worked just fine.

So, this winter I stored the boat in the garage as usual with the forward
battery hatches open. I also jacked up the retractable roller so the boat
has more of a stern-down orientation while I store it. I have not smelled
gas odor since.

Perhaps I overfilled my tank when I first got the boat. I was reassured by
the thorough inspection accomplished by the dealer and at this point, I am
just not going to worry about it until there is a problem.