Water in boat gas tank , after being cleaned out, more then condensation?

Question

Water in boat gas tank , after being cleaned out, more then condensation?

Answer 1

Could be due to ethanol in the gas.  Ethanol is extremely hygroscopic, which is to say that it absorbs almost all the moisture out of any air with which it has contact. Normal condensation will result from pressure and temperature changes causing the gas tank headspace to 'breath', with the result that condensation will develop and settle. Ethanol exacerbates that problem by insuring that all moisture gets trapped in the tank. Ethanol and boat gas do not do well together.

Answer 2

Ethanol blended gas is terrible for marine applications. It will go bad, and become water contaminated very quickly. In order to combat this you should always use a stabilizer, preferably Marine Sta-bil. It is much more concentrated than regular Sta-bil, but either will work.  

Answer 3

Check the tank sender if the gasket is not sealed>Gas cap leaking> Your supplyer for water in his tank> Install a water supperator> With a drain>

Answer 4

Steve T may be correct- depending on the insulation around your tank, condensation could be a problem. If you install a Racor filter with a water separator, you'll be on the right path. Check the separator bowl frequently at first to get an idea of whether you're getting an unreasonable amount of water.

Answer 5

The o-ring on the gas cap may be missing and water gets in. Also, the fuel tank vent on hull side could be turned downward and water is forced in from waves splashing. Happened to a friend!