[G.R.]

Old fuel fill hose absorbs gas odor. In my FIA i had two problems of fuel odor, #1 was a leaking fuel-sender gasket replaced that and still had the odor, discovered after filling the tank I still had the odor, did the "sniff test" yup came from the filler hose to the tank.
I replaced the hose&vent line with marine type fuel hose from West Marine. It is non-permeable for use in boats to eliminate the diesel smell, gas won't hurt it either. Expensive though about $3.50 a foot.

NO more fumes/odor in the boot.

I had the same problem on our boat several years ago. Fill the tanks,close the boat up for a week, come back and the diesel smell would darn near knock you over. Replaed all the Filler hose and vent lines problem went away