water in the tank???

[T-water]

I was in Grand Rapids last week one evening we had a huge downpour. The next day my gas tank was floating in the back of the boat. My Bilge pump died after a few minutes (aaargh) so I started up the motor and opened the plug. Eventually the motor died used the electric motor to get back in. After lots of screwing around we drained water out of the gas tank via the fuel pump and then restarted the motor. So all is good now but...I cant figure out how the water got in my tank. I did have the the vent minimally open but we drained way more water then could have gotten in from that. I'm pretty sure there isn't a hole, never smell gas or seem to lose gas. Any ideas? I'm assuming I need to get a new tank.

[Surface Tension]

Expansion and contraction.

When the gas and air in the tank cools down it'll contract, when it does that its going to suck air in threw the vent. If the tank is in a puddle of water it'll suck water in.

[solbes]

That seems to be a solid theory. I recently spent a lot money at the dealer to suck out my water/gas mixture. I think I had a similar thing happen to me.

Too bad I didn't suspect water intrusion in the first place, I could have saved a lot of money. $60 to fill up the tank, $270 to suck it out, and $60 to fill it back up again. A little bit of knowledge, priceless!

[T-water]

Contraction!!! Good stuff but I have to assume the seams on the tank are bad because the tank was covered and floating. Time to get a plastic tank!

[Surface Tension]

You said you left the vent open. A steel tank when floating in water will flip over(vent down) ever time.

[BillP]

I am NOT an outboard mechanic but over the years I have found that most any time you are having trouble with an outboard (particularly when you are taking it out of winter storage) it's well worth checking for water in the gas tank. I made a little gimic that works great. All you need is a length of thin copper pipe, a couple of feet of hose and a priming bulb from a gas line. Set the tank up on something and prop one end up so the lowest part of the tank is positioned so you can easily put the pipe through the filler hole with the end in the low spot. You have probibly shaken it up so wait for the water to sink to the low spot. Put the end of the pipe down into the low spot and the other end of the hose lower than the tank aimed at a clear container. Give the bulb a few pumps to get the siphon started and watch what comes out. You may also want to get the water out of the gas tank hose since you pumped it in there trying to start the motor. Just press something into the motor end of the hose to open the valve and pump your priming bulb till you get nothing but gas.

[IFallsRon]

A shot of gas line antifreeze with iso goes a long way toward reducing water problems.

[solbes]

Yup, good call. The dealer did get most of the water out using a somewhat similar method (thus the $270 charge). And I did use some ISOpropyl alcohol to help remove any residual from the tank.

Guess I'll try checking it more often until I'm aware of how it happened in the first place.

[BillP]

Once in an emergency I just used a length of soft copper tube. Darn, that gas/oil mix tastes terriable