Help to drain fuel tank

[Streaker]

I have just noticed that the fuel tank is full of water, I can't explain how this has happened and I need some advice on how to empty the tank. The filler point is high on the gunrail and the tank is sealed under the floor, it's a 180 litre tank. I have tried to syphon the tank from the filler and to disconnect the fuel line from the motor and syphon from there but it does not work. Do I have to remove the floor, any advise would be helpful.
Wayne

[FNQCairns]

How high is the nose of the boat, raised on blocks even? To get a syphon going the tank needs to be as high as possible in relation to the level of the fuel in the container being syphoned to. Syphoning always works even if a little slow because if the engine can draw fuel then it can be syphoned out, you may need to increase the length of the end of the fuel line but it will work, crappy job though.

You can also poke the fule line out a bung hole if possible.

cheers fnq

[SNAPPERCOFFIN]

Disconnect your line to the motor then block your breathers then use compressed air down your filler area to force the fuel out make sure the nose of the boat is up high as the pickup is usally near the back of the tank. Then put a cup or two of metho to disperse any left over water. If you have a side filler check the oring on the cap water could be getting in there.

[Streaker]

Thanks fnq
I just extended the syphon line to about 25 metres and the land is on a slope so the process has begun. This could take some time though. What about the bit that will be left in the tank would put some metho in to disperse it.
Wayne

[gofishin]

...You can also poke the fule line out a bung hole if possible.

cheers fnq Yep, the bungol works for me! Get yourself a shortish piece of 3/8 fuel hose & put a primer bulb on the end. Disconnect the fuel supply out of the filter (hose to the motor), thread the 'syphon' hose through the bung hole & connect to the fuel filter outlet (cartridge will be stuffed anyway, so no problems pulling more water thru it). A few pumps & your away - so long as the syphon outlet is lower than the bottom of the tank. Just remember to keep changing fuel/tote tanks as required.

Next problem is that you will probably need to remove your tank, as you will NEVER get all the water out. The pickup will not remove the small amount of water remaining in the tank. Does it have an inspection port or sender located over the deepest part of the tank? You could sponge it out (on a wire) - tedious but doable. be very careful!
cheers

[Streaker]

another great idea snappercoffin. I have just phoned the owner who happens to be builder and he is on his way. The color of the liquid being removed has gone from clear to slighly fuel color, would you still drain all the tank.

[gofishin]

Just saw the other posts after i had posted. Metho should not be used with today's injected motors for the same reasons as why ethanol is very bad when it has combined with water. As stated, you should remove all remaining liquid in the tank.

Using compressed air is very risky and dangerous. Rember your tank was only tested to about 3 - 5 PSI, which is very minimal. a 25m syphon hose is going to be a very slow process due to the friction losses in the long hose.

[Streaker]

Thanks gofishin
I will let he owner know.
A big thanks to you all for your help on this.
a good deed done is a good deed owed.
Wayne

[SNAPPERCOFFIN]

A bit of air wont hurt it doesn't take much to speed up the draining process. Also metho will eat up the water then evaporate if you dont want to take the tank out. Fully draining the tank in the boat depends on how the pick up is even in the best position you will not get it all out.

[tunaticer]

If you are going to use compressed air you must regulate the pressure to a max of 5 psi, 2 psi will quickly drain a tank anyway. Depending on your pickup position and dimensions/design iof your tank you could well have up to 20 litres of water still remaining in the bottom of your tank after this process so you may be forced into removing it either physically or by some other means.

I have seen a guy effectively remove 99% of the water with a face washer fixed to the end of a wire to mop the remaining crap up with, his access was fairly straight and took a hour or two to remove about 3 litres from below the pickup level. I guess there is a risk of losing the washer down the hole if its not secured properly but in that case its down to tank removal once more anyway.