To pressure test the tank should be empty and no more then 5 psi. More pressure then that is dangerious
Best way to get the tank out is cut it out. I thought mine was reusable so I got it out in whole and it was a bugger to remove. After removal it turned out it was ok but had some thin spots, so I replaced it anyway.

Got tank from Florida Marine and Tank

3 PSI is generally safer and will tell you what you need to know. Even 5psi may damage the tank itself, if it isn't already.

Please do not pressurize your fuel tanks. Lets say your tank is 2 ft by 6 ft. That's 1728 square inches on top. Put 5 psi in the tank, now you have 8640 lbs on that top surface. If the tank hold, it turns into a big football.

Agree, 3 is safer my mistake, and no pressure is even better

New tanks are tested at 1-3 psi.

I could swear there was a young guy that had a 21 scarab that pulled it all apart to fo some stringer work, cust interior and an LS engine install. Within 10yrs from now ?

Was a few yr pretty detailed thread.

Maybe thread would give you some gas tank removal and etc ideas/help ?

yes, it is a lot of force. I just made some tanks, and pressure tested them @ 3PSI. my tanks are 25" x 81" topside = 6,075 bs of force on that top plate. It bowed out about 2"+

Take that to 5PSI = 10,125 lbs of force, too muchy!

Also, get yourself a regulator to knock down incoming air into the tank. So you initially let ZERO air into the tank and then turn it up until you're just under 3 PSI.



That's a calibrated pressure gauge I have on there to really see what I'm doing. We have tested tanks to just under 6,000PSI here at up to 4" wall thickness. That's a lot of force, and it's no joke even just a few PSI. We do not air test here as that's too much stored force (potential) if something were to burst. The safer way is to hydro test as water is incompressible and has much less stored/potential force. BUT people don't readily own hydro test pumps and setups.

Additionally, I bet 80% of people out there are operating / own those portable air tanks that are out of date. The tanks corrode away and compromise integrity (AKA - explode!). There are safety factors built into the code, but alot of manufacturers reduce wall thickness to nothing, to reduce cost... And one more thing - be weary of air compressors that have been out of operation for periods of time, they can corrode and go boom! when pressurized. Serious stuff not a lot of people think about. (Also remember to bleed / drain your air compressors of water. Some fancy compressors have desiccant systems - better known as air dryers.)

Id suck all the fuel out let it set of a couple days open empty, flush with water and then pressurize it so it don't go.........boom

I sucked as much fuel as I could out, then filled with water, drain repeat, left to dry out for a few days then I ran vacuum sucking out any fumes while I cut it out with a sawzall.
I did not enjoy that at all.
For finding leaks a smoke machine is the best tool ever. Ive easily found intake and chiller leaks with smoke.

Thanks for all of the great insight guys. I am taking the boat tomorrow to perform a smoke test and see what I come back with. I'm feeling more and more certain it's the tank leaking as I read all of your responses. Even if it is coming from elsewhere, I'm still inclined to replace it as it does look pretty corroded up top (can't imagine how it looks below). I'll report back with my findings.


Thanks!