Most of the well meaning folks who say that the A4 and gasoline engines are dangerous (Atomic Bomb) most likely have diesel engines and may never have owned an A4.
Besides using the blower before/after running your engine as mentioned above, it is a good practice to ALWAYS shut off your main fuel petcock (valve) before you leave your boat. This insures that the fuel in your tank stays in your tank and does not find a way into your bilge. Of course, this means you will ALWAYS have to turn on the fuel valve when you get to your boat. It is also a good practice to shut off your raw water valve when leaving the boat and opening it each time you arrive.
If you haven't been to the Moyer Marine forums you owe it to yourself to register over there: Moyer Marine Atomic 4 Community - Home of the Afourians - Powered by vBulletin
There are a number of A4 owners over there who have owned their engines for many, many years and can offer assistance, if needed.