1999 Mercury 150 hp EFI fuel leak question

[flashmob]

Bump (I have had this motor since 2006 and in the last 3 months I have boat out 3 times on 2 of the trips when i got home and trimmed motor up a half a pint or so of gasoline has poured into spillway overflow.I took it to my mechanic the first time and he said he let it run for awhile and it didnt do it again .He said he inspected it for leaks and didnt see any . It didnt do it the next trip out but did on the following . Has anyone had this happen ? I have thought about adding an additive to maybe clean the injectors or something . I have only used 87 gasoline but i use stabil ethanol treatment every tank since they started using ethanol in gasoline .Motor runs strong and no missing . Only this fuel leak problem all of a sudden .Any advice would be appreciated .

[JOE54]

check all external connections , it would have to be a massive leak internal to be rail related throttle body should be sealed from a tilt leak at bottom, try v6 section one down for more info with ser number