Here's kind of a expensive, but seems worthy idea to keeping your fuel vent(s) from allowing moisture laidened air into your fuel tank(s).
Might really be a good idea in the excessively humid parts of the country, as in J-ville Florida where I'm at, the mean avarage humidity levels always seem to be 90% plus.
Not cheap, but claims to do the job,
Whatcha think??
https://www.pindellengineering.com/H2Ou ... ation.html
I have two vents, one to front of tanks, the other to rear of tank.
BUT... before that fuel enters your tank, do you know if it's "watery" or "Dirty"
Here's a explanation of a product that can help.
http://youtu.be/J2TUgxTjHfc
""Mr. Funnel" by Shurhold, on Ship Shape TV
"I fish and surf, web surf....it's what I do."