Gas Tank Removal Options

A

aberrant

New Member
Jun 17, 2019
10
Boat Info
1986 SRV230
Engines
Mercruiser 260
I've been tracing a gas leak/fumes for a day now and all the lines and sending unit look solid. There's gas in the bilge and when I look down the sides of the aluminum gas tank it looks shiny at the bottom. I'm assuming the worst with pinhole leaking on the bottom of the tank. I'm trying to determine the best way to remove the tank. I don't think I have enough room to pull the tank out through the large opening so what I'm thinking is to cut the support closest to the engine to give me enough room to pull it up that way.

Has anyone done this on an 1980s SRV? Does this make the most sense or does anyone have a better idea? Also, should I replace with a plastic tank or another aluminum tank?

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The last one I did that vintage about 20 years ago we ended up pulling the engine and dragging it out through the engine bay. I never was crazy about cutting up a bulkhead. Gives you an opportunity to get the bilge cleaned and check stringers/mounts as well.
 
Thanks for the reply, I measured the tank at 50"x25" there isn't enough room to drag it out even if I removed the engine. I only have about 40" from the transom to the front of the engine.
 
I would look at getting a smaller one that would fit back in. And then cut the old one out.
 
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Cut an opening in the side of the hull and slide it out sideways. That is the way these repairs are routinely made on large boats. It is easy to repair the opening you create. Be very careful of the fumes. Experience and expertise are required. I've heard of nitrogen being introduced into the tank when it is empty, but have no firsthand knowledge of how that is done. Darwin awards come to mind.
 
spikedaddy99 said:
What the heck will you cut old one out with, with gas fumes present?
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Well first I would light my cigarette. If I'm still there, then we are good to go. :)

Obviously you need to take precautions and be careful. Drain the tank, drain the bilge, rinse everything off, and make sure there are no fumes. I would probably hit it with a cutoff wheel and a hammer, till is was small enough to lift out.
 
scoflaw said:
drain the gas and flush with water
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Doesn't work, tried it with a motorcycle tank. needed to weld a crack and flushed it 3 or 4 times then filled it with water, soon as i struck an arc there was a poof and I now had a tear dropped shaped tank! Gas imprenates the metal and you need to disipate the oxygen. Get a bottle of argon and fill it with that and keep a constant flow thru tank and you'll be good, that's how I finally welded another tank.
 
atrick said:
Doesn't work, tried it with a motorcycle tank. needed to weld a crack and flushed it 3 or 4 times then filled it with water, soon as i struck an arc there was a poof and I now had a tear dropped shaped tank! Gas imprenates the metal and you need to disipate the oxygen. Get a bottle of argon and fill it with that and keep a constant flow thru tank and you'll be good, that's how I finally welded another tank.
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Just replaced an aluminum tank in an 82 Aquasport with this technique.

Gas impregnating aluminum, eh ? Not going with that one.
 
atrick said:
Doesn't work, tried it with a motorcycle tank. needed to weld a crack and flushed it 3 or 4 times then filled it with water, soon as i struck an arc there was a poof and I now had a tear dropped shaped tank! Gas imprenates the metal and you need to disipate the oxygen. Get a bottle of argon and fill it with that and keep a constant flow thru tank and you'll be good, that's how I finally welded another tank.
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Argon +1. That's what we used to do.
 
Go with a plastic tank. No corrosion issues, they are just as safe and as good as metal and since they are roto-molded, no seams to leak. They come in all shapes and sizes. They are pretty much all made by Moeller now. I have one in my SRV 190. 26 gals. Like you I have to remove a lot of stuff to get at it. But I only had to do that when I first bought the boat to clean the tank. It had been sitting for ten years. I've had the boat 8 years, the owner before me had it ten, and the tank was in it when he got it. So it's been around for a while. The boat is a 72. I do not think the tank is the original because the brochure for this boat says it's 18 gal. So someone put it in.
 
It only take a few hours to remove the engine (given the experience and tools, of course). A few extra hours if it's your first time. Then you should be able to slide the tank aft and tilt it up and out. Plus, once you get those cockpit floor "wings" out, it'll give you a little more wiggle room.

A common source of leaking is the bottom side of the tank - not as much was known about installation techniques back then and often the tank stayed in contact with something (keeping moisture in contact with the tank) or rubber strips were used against the tank (rubber is corrosive to aluminum).

Plastic is easy from an 'anti-corrosion' standpoint. Aluminum can be made to any size you want easier than plastic.
 
I had a custom fresh water tank welded to my exact size and shape last year.

It was no more expensive than a roto molded tank and there were no limitations at all.

Also, I’d have to have no options left before I sawed a hole in the side of my boat.
 
Your first aluminum tank lasted 34 years so I wouldn’t be afraid of replacing it with another aluminum tank if you can’t find a suitable plastic tank.
We had a plastic tank collapse on my Uncle’s 1995 22’ fishing boat a few years ago in a spot where the sender is secured. It resulted in a water leak in to the tank when he washed the boat or in a heavy rain.
The boat had two tanks so we figured the other one wasn’t far behind.
Had a fiberglass guy cut the deck open and after unsuccessfully trying to find suitable sized plastic replacements we has a tank guy make up a single aluminum. Cost two or three years ago here on Long Island NY was $8.00 a gallon with a $200.00 minimum (we needed a 65 gallons tank anyway).
The price included all fittings, sender, etc..
We installed it with new hoses and had the fiberglass guy reinstall the deck.
 
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