On Fri, 18 May 2012 13:01:51 -0400, "Wilbur Hubbard"
wrote:

Water in fuel tanks is a common problem. It would seem to me that built-in
tanks should all have a small sump at the lowest part with a drain valve
to check for and get rid of any water that collects from condensation or
water in the fuel from dubious sources.


Water in fuel tanks is a common problem but ABYC and USCG standards,
not to mention your insurance company, require that gasoline be drawn
from the top of the tank with a dip tube and no sump drains are
allowed. The risk of gasoline leaking into the bilge is too high.

In lieu of that, you should install a large fuel/water separator filter in
the intake line and check and drain it frequently.

That is the right solution but if mounted below decks with a gasoline
engine, the filter is not allowed to have a drain fitting.

Chances are that the engine initially ran OK because the water level
in the tank was below the dip tube pickup. Dip tubes never go all
the way to the bottom. As the boat moved around while underway,
water got picked up as the fuel sloshed around.

Detecting and getting rid of water in the bottom of a permanently
installed gasoline tank is difficult because no sump drain is allowed.
If your fill pipe goes straight down into the tank from the cockpit
you can put water sensing paste on the end of a stick and dip it to
the bottom. If the paste turns color, usually red or purple, you have
water on the bottom. The only way to remove it is with a plastic
tube and small transfer pump.

Google search: gasoline water sensing paste

http://www.google.com/#hl=en&gs_nf=1&gs_mss=gasoline%20water%20s&cp=28&g s_id=32&xhr=t&q=gasoline+water+sensing+paste&pf=p& output=search&sclient=psy-ab&oq=gasoline+water+sensing+paste&aq=f&aqi=&aql=& gs_l=&pbx=1&bav=on.2,or.r_gc.r_pw.r_qf.,cf.osb&fp= ca5e4e80e08f4ec0&biw=1015&bih=612