Oh Boy...This Smell Ain't Good

[TownsendsFJR1300]

I'll check out your tank business recommendation, thks. Have you ever pressure tested a tank? Wondering what's the common method to seal off the 3 fittings and 1 big sender hole.

I have no affiliation with them, just looking on-line...

Re pressure testing, put the sender back in the hole and close off all other holes with a rag/ plastic -milk jug, duct tape, but leave a small opening for an air compressor fitting.

You don't need 100 PSI, (it sure would show ALL LEAKS THOU!), but put positive air pressure in it, spray with windex, / soapy water and look for bubbles (just like a tire tube with a slow leak).

I'd hit the top of that tank with a large wire brush to knock ALL that corrosion away (which can hamper your hunt for leaks)

You can (as it needs repair anyway), put sheet metal screws in each hole as you go along till you have no more bubbles...

A 4' x 10' sheet of aluminum, 1/8", was just over $100 (last time I bought a sheet) so the material isn't that bad $ wise. It's the welding that'll get ya..

.

[boscoe99]

I know those poly tanks have become popular lately. I don't know anything about them. I'll have to read up.

Have these poly tanks been in service long enough to determine their long term durability?

I had a 100 gallon plastic tank in my 1998 Aquasport. Nary a problem with it. I am pretty sure that the technology has been advanced since that time. It was made by Moeller.

The plastic surely seems to outlive aluminum, particularly in a salt water environment.

Permanent Fuel Tanks | Moeller Marine

[Jason2tpa]

First: Home - Tampa, FL - CL Mattson & Company, Inc Near you!

That corrosion is from water / condensation sitting atop the tank in a nice
closed environment that doesn't let it evaporate.

My neighbors old Mako had a similar issue right near the filler, (on the tank). His tank was foamed up top too which helped hold in moisture and his leak was very obvious, discolored foam. As his was very limited, he put some sheet metal screws in the holes, then epoxied them. No issues after that..You did get 19 years out of this one, so really not too bad...

I'll check out your tank business recommendation, thks. Have you ever pressure tested a tank? Wondering what's the common method to seal off the 3 fittings and 1 big sender hole. The tank is 1988. So almost 30 years. Be that as it may, I sure wish the previous owner had replaced the tank.

[TownsendsFJR1300]

I know those poly tanks have become popular lately. I don't know anything about them. I'll have to read up.

Have these poly tanks been in service long enough to determine their long term durability?

If you can find the correct size and get a plastic one mounted (and the expanding foam helps a BUNCH holding it)...

You did get 19 years out of this one, so really not too bad...

[TownsendsFJR1300]

First: Home - Tampa, FL - CL Mattson & Company, Inc Near you!

That corrosion is from water / condensation sitting atop the tank in a nice
closed environment that doesn't let it evaporate.

My neighbors old Mako had a similar issue right near the filler, (on the tank). His tank was foamed up top too which helped hold in moisture and his leak was very obvious, discolored foam. As his was very limited, he put some sheet metal screws in the holes, then epoxied them. No issues after that..


I noticed, years back (and my tanks a year older than yours) of a wet dust atop my tank (looking thru the access hole in the deck). There were a couple of spots (no where near yours, maybe 1/4 of yours, size wise) of white corrosion ATOP, (like yours), very small but obvious (not leaking).

My tank DOES have maybe 2" between it and the deck cover(ie air flow). I snuck a clean rag in there with a 3' wood yard stick and got rid of all wet "dust". The couple white spots, I cleaned best as possible and snuck a small paint brush with acrylic (not water based) paint and painted over those spots... Stopped any further corrosion.

[Jason2tpa]

The future is in plastics.

I know those poly tanks have become popular lately. I don't know anything about them. I'll have to read up.

Have these poly tanks been in service long enough to determine their long term durability?

[Jason2tpa]

It's an aluminum tank. Get the unit out and examine the rest of it as well...

As nasty as the top looks, that aluminum is really thin.

Depending on how the rest looks, at a minimum I'd either be replacing the entire TOP section or the entire tank..

I would NOT be taking any shortcuts with this, your literally standing above a potential bomb..

No shortcuts intended, agreed. Your thoughts on the cause of those small holes? Saltwater corrosion, I'm assuming.

Here's the fuel sender. You can see how warped the gasket is. No doubt fuel was spewing from here.

[Jason2tpa]

Find a good tank man and let him do the job.
Big $5000 job putting in and taking out that tank and replacing with a new one. You need special tools and saws.

That Al tank is 1/4 inch thick. You'll likely destroy it taking it out and need to buy a new one.

Nah, that's foam you see surrounding the tank. You cut it out, piece by piece. Remove all the foam on one side, pull the tank over to that side, remove the foam from opposing side. Arduous and laborious, yes.

[boscoe99]

The future is in plastics.

[TownsendsFJR1300]

It's an aluminum tank. Get the unit out and examine the rest of it as well...

As nasty as the top looks, that aluminum is really thin.

Depending on how the rest looks, at a minimum I'd either be replacing the entire TOP section or the entire tank..

I would NOT be taking any shortcuts with this, your literally standing above a potential bomb..

I gather you'll likely need a company that specializes in tank repair, sales...

[ausnoelm]

Replace tank, do it right and do it once, patches of epoxies and stuff like that are just buying time.

[Jason2tpa]

More pics...

[Jason2tpa]

Update:

Fuel floor panel came off easy, silicone sealant. Pictures are below pretty much tell the story. There was a yellow paper thin layer of dried fuel on top of the most of the surface area of tank. By looking at the condition of the sender gasket, as well as how much flakey corrosion was surrounding it, my guess is fuel was leaking from here. And probably for quite a long time. After scraping most of the layer of crusty off the tank I found 4 small holes. The diameter of these holes are about the size of the tip of a blunted lead pencil tip...1 or 2 millimeters. In the pictures I've circled each puncture site with a black marker. So far these are the only holes I've discovered. 1 hole next to sender, the other 3 starboard aft of tank.

I think it's safe to assume the bottom of tank is not leaking because the tank remains at least 3/4 full, no fuel leaking into bilge. The tank was manufactured by EVER-NU Tank Corp, Pompano Beach, FL. Manufactured date is 1988, 29 gallons. The "Const. Mat." is 090. I'm not sure what that indicates. The code for aluminum, SS?

So now's the time to chime in after looking through pics. Please let me know what you think. Replace tank? JB weld the puncture sites and replace fuel sender/gasket, then pressurize tank to confirm no other leaks? I'm headed back to the boat now to siphon out fuel, clean up the tanks surface a little more for better inspection.

This first picture is what the sender looked like before I started scraping

[rodbolt17]

I forget the brand but there is a product in a spray can that debonds 5200.
it is wonderful stuff.

[TownsendsFJR1300]

Plus 1 on using your primer bulb attached to a longer hose, then to another tank.

How much fuel comes out will give you an idea where the leak is. No fuel, the leaks towards / at the bottom...

I wonder if it's an aluminum or plastic tank that cracked maybe at a mounting point.

I'd get some real sharp razor blades and simply start cutting down the middle of the sealer to break it loose. I doubt they squeezed it super deep into the crevice. All you have to do it break the seal, then clean up the edges/ what's left later...

Hopefully, it's an aluminum tank that can be re-welded or a patch applied.

Once out, simply pressurizing it with some air, and squirting with windex will show you your leak (if not already visible once out).

Me thinks the PO, with the trailer issue, now this, hasn't been completely forth coming with the sale..

Good luck, find some shade as it's going to be a hot one today..