Exhaust in cabin

Found a small rip in the seal not sure what its called that the filler tube in the trunk for the gas,sealed it up and got a new cowl to hood seal as to redfish advice,now the only time we get a wiff of fumes is on start up,I am thinking tool man is on to something,after our cruise in last night Cindy even said we dont smell like exhaust no more.Thanks all for the help,next is to look at the column that is were it seams to be coming from on start up.