Taking fuel tanks out of a fiberglass boat

[FishingNut]

I am having fuel issues with my Olympic that has been in storage for the winter. Gas is showing up in the bilge and has at least ruined the float switches. I'm looking for advice on testing the tank to see if there are leaks as I really would like to avoid cutting into the fiberglass deck if at all possible. If I do have to cut into the deck, I would appreciate any advise you may have about that process as well.

Thanks for the help.

[MacGyver]

Leaking gas, fumes in a enclose space !!!!! :eek: Unless you know what you were doing I would let a professional test the tank. There are so many ways you could kill yourself if you were not careful.

[oldmil007]

Not bad advise there Rutting Moose.

Nut, I sent you a PM that may be of help. Wish I lived closer - for more reasons than one!

- Jay

[bkmail]

My Aluminum tank began to leak in the figerglass boat shortly after I bought it. At first it was a faint odor when walking by the boat. Then it gradually turned into a few drips out of the bilge. I siphoned out the gas with a long extension added to one of those "rattle siphons" Wal-Mart sells.
Then I took it to CAC Plastics in the valley to have them remove the tank. Since the tank was nothing "standard" that anyone carried, I had Greatland welding remove the bottom and put a new sheet of aluminum on it.
I reinstalled the tank and put the fiberglass "cap or deck piece" back on at the house. The fiberglass "cap" I secured to the deck with marine adhesive and stainless screws. In the future it is removable in the event I need to get in there again.
Total cost was $1500-.
BK

[rmk4x4]

i would take all the gas out and cap off your fill and vent and put an air fitting on the supple line and see if it will hold 3psi or so do not go more than 4psi

[MacGyver]

Good idea, now you have a fuel tank filled with gas fumes and air under pressure. If the tank does hold how are you going to release the pressure, with out killing yourself? There also the problem if you use the wrong size gage you could over pressure the tank.

[rmk4x4]

Good idea, now you have a fuel tank filled with gas fumes and air under pressure. If the tank does hold how are you going to release the pressure, with out killing yourself? There also the problem if you use the wrong size gage you could over pressure the tank.

ok fill it co2 if you wanted to be safe but i would really not worrie about it. i have done this manny times i have also built lots of alum fuel tanks i dont see the problem it not like he going to weld on it full of a air gas mix. you could even fill it with colored water and then pump it out and flush it a few times if it does leak pump it out and dont worrie about it.

[RustyMonkey]

When you are running your boat what psi is your tank under? I just had a spot weld done on my tank and am curious. Is a psi test necessary? I have filled it with water and it does not leak anywhere.

[MacGyver]

Fuel tanks are not under pressure in boat that I know of. The reason for doing the test is it the only way to guarantee there are no leaks anywhere on the tank at anytime.