Determining condition of original aluminum fuel tank

[CobbFisherman]

I have a 1998 Parker 1800. I bought it about a year ago, and have put about 170 trouble free hours on the boat so far.

It has the original aluminum gas tank.

When I got the boat it was running fine, but i still drained the tank and then flushed several gallons of fresh gas + Seafoam though the tank and lines. Minimal crud came out. I then used a mechanics borescope to visually inspect the inside of the tank. It looked fine, with no gunny deposits or noticeable corrosion. The tank does not leak.

All the talk on this forum about replacing old aluminum tanks has got me wondering: How do you know when your old aluminum tank is bad? (Aside from the obvious like a leak.) Will you get white powdery aluminum corrosion/oxidation residue in your fuel filters? What should I keep an eye out for?

 

[warthog5]

The answer is......You Don't........You smell fuel and investigate.

Bore Scope........How did you get past the Baffels?

I suspect you went thru the motions, but really did not get a good look.

 

[CobbFisherman]

I went through the sending unit hole. I was able to un-bolt the sending unit through the pie pan access hatch and lift it up far enough to put the bore scope in.
It was a real pain, but all the fuel tank replacement talk on this forum made me nervous.

You're right though, I could not get it to snake down through the filler neck, as that was my first failed attempt.

 

[Puck-n-Fish]

I still have my original tank (1997 1800). Had I not joined this site last year, I would have never known about the tank issues. All I do now going forward is be aware of any water infiltration in that area and keep it dry. Don't let it worry you. Enjoy the ride and it you have to cross that bridge later, feel good about having access to all the knowledge and experience from others here that have re-tanked. It doesn't scare me anymore!

 

[warthog5]

Yes..... Going thru the sender hole is the only way in.....Typically there are 2 baffles, They consist of the same thickness alum and devide the length of the tank in 3 parts. The corners are clipped off to allow fuel to transfer from front to back......getting a bore scope thru where they are clipped off is iffy on the first one and dang near impossible on the secound one.......and my point was........Inspecting the inside is Impossible.

 

[CobbFisherman]

Oh, so you're saying that I only saw a small portion of the tank between the baffles inside the tank where the sender unit hole is. I guess I just assumed those baffles were the edges of the tank, its hard to judge depth/size with a small scope. Bummer. I thought you meant the baffles in the filler neck, which I couldn't get the scope past.

I guess I'll just not worry about it until my bilge starts to smell like fuel...

 

[tomc585]

I doubt youll see anything from the inside. Tanks mostly suffer corroision from the outside in.
Just monitor your tank by noting any smell of fuel below the deck, in the bilge and console. Low presure (3-5lbs) testing can be done but you may create a leak if the tank is questionable.
My 1801 had a slight smell in the console, turned out to be the OEM fuel fill hose which was dry rotted and seeping fuel.
Keep those inspection ports from allowing sea water in and inside the console where rigging comes up from below. This is where the corrosive sea water gets to the tank. Rigging tube risers should have been glassed in inside the consoles but thats just me.

 

[Brent]

I will add to look at top of tank and fuel sender hole . If top is very dirty might look for bad spots. FWIW Scope can also be placed through fuel fill. I had my tank cleaned and pumped out using fuel fill and sender openings. They didn’t see any bad spots with flashlight using lots of bad gas. Sender screw holes were ok and they added new gasket. This is on 94 2330 original tank. Top of tank was dirty but no signs of either deck hatches leaking or bad deck wood when I replaced hatches. I replaced the hull vent fitting with a flush unit and added a P trap per Warthog. Keep posting updates

 

[Brent]

I will add to look at top of tank and fuel sender hole . If top is very dirty might look for bad spots. FWIW Scope can also be placed through fuel fill. I had my tank cleaned and pumped out using fuel fill and sender openings. They didn’t see any bad spots with flashlight using lots of bad gas. Sender screw holes were ok and they added new gasket. This is on 94 2330 original tank. Top of tank was dirty but no signs of either deck hatches leaking or bad deck wood when I replaced hatches. I replaced the hull vent fitting with a flush unit and added a P trap per Warthog. Keep posting updates

I installed remote Racor 2 micron fuel and water filter with drain bowl. I pour off fuel into clear jar to inspect gas color, water and debris. Tank cleaning and all new gas helps a lot along with new vent and sender gasket

 

[Bodick93]

Oh, so you're saying that I only saw a small portion of the tank between the baffles inside the tank where the sender unit hole is.

Yes but you saw a great representation of the tank condition. Good work.
I put sealant on my pie plates. I bought a $30 wifi borescope a few years ago and use that for inspections under the pie plates. I run it from the bilge side opening to the tank.

 

[warthog5]

Oh, so you're saying that I only saw a small portion of the tank between the baffles inside the tank where the sender unit hole is. I guess I just assumed those baffles were the edges of the tank, its hard to judge depth/size with a small scope. Bummer. I thought you meant the baffles in the filler neck, which I couldn't get the scope past.

Correct..........There are No baffles in a Filler neck

 

[meapollo]

Have you tried pressure testing your tank? It is quite easy. I did it on my 2520 aluminum tank and it was easy. Just a few fernco fittings from home depot to block all the ports and a gauge and fill stem from harbor freight and it was a done deal. I did seal the outside of my tank with some epoxy a buddy gave me from a refinery he works at. Said its the best stuff. I'll have to ask him again what its called cuz the can was unmarked.

 

[Brent]

I would be skeptical to pressure checking my tank and be very concerned about over pressuring tank and damaging it. Fwiw

 

[big_tuna]

just keep your fingers crossed.