Fuel Tanks

wileecoyote

wileecoyote

Member
TECHNICAL Contributor
Oct 18, 2008
949
Southern MD/ Potomac river
Boat Info
1989 340 EC
Engines
7.4LX2 Hurth 630A Drives
6.5Kw QS Genny
I've been asking alot of questions concerning the 1989 340EC I am purchasing. My surveyor has recommended that the fuel tanks be replaced within the next 3 years. I'm almost certain this involves removing the engines as well. Does anyone have any ideas on this? He said there are no current issues, but that is the useful life of an aluminum tank. Thoughts?
 
If you don't receive any replies, you may want to drop a PM to one of the Franks.....either FC3 or Frank Webster. I'd like to think an aluminum tank would last forever so as long as abrasion doesn't rub through it....but then again, 20 + yrs is a long time. Good luck, the 340EC is a nice boat.
 
I think your got a surveyor with a case of CYA syndrome.

As long as your tanks have not had water in them, aluminum should not be a problem. Ethanol in fuel can cause issues with blow-molded tanks and the ethanol is hydroscopic......i.e. attracts and absorbs water.....so your tanks may be holding some water and water will cause corrosion in aluminum tanks.

So, did your surveyor test your tanks for water or is he just covering himself for the possiblilty.

The other thing I will tell you is that changing fuel tanks on a 340DA or EC is one hell of a major job......one I'd avoid if at all possible.
 
He did not take any kind of readings, just a visual of the tanks, but told me I should be planning in the next few years to plan on replacement. I'm pretty sure this includes removing the powerplants, so if I have to do that, I will replace them then. Thats why I was asking, I was hoping others would feel the same as me. Thanks!!:smt038
 
Last year I tried to take a look at my fuel tanks, on my 340DA they are located under the floor of my aft cabin. I would have to tear up the floor, even to look at them. As long as they don't leak, let them be.

As Frank stated: " One hell of a major job" !!!
 
wileecoyote said:
I've been asking alot of questions concerning the 1989 340EC I am purchasing. My surveyor has recommended that the fuel tanks be replaced within the next 3 years. I'm almost certain this involves removing the engines as well. Does anyone have any ideas on this? He said there are no current issues, but that is the useful life of an aluminum tank. Thoughts?
Click to expand...

I was looking at the same thing, but for differant reasons. My tanks are only 65gal each. Why SR put in such small tanks.....I want to put in bigger tanks, but I may have to remove the engines.
 
The 300DB has a center of gravity well aft of where it should be for the boat to be efficient as it is. If you add larger tanks in the same location your boat is going to be even harder to get on plane and it will require even more power and fuel to keep it there.

If you add larger tanks, consider doing it with added tanks or tank in a forward location.
 
I will have to look at the tanks again to see if there is any corrosion. He told me that he didn't see anything, but they only should last about 20 years. When I get it back here I will be doing a more in depth inspection, then I'll have lots of questions! I believe my tanks sit ouboard of the engines, I can't imagine how bad replacing the DA tanks would be, thats a disaster!
 
Ok, then let's do this.............call the surveyor and ask him this question: "What would cause my aluminum tanks to need replacement?...then listen. If he gives you reasons, then ask "Do you see evidence of this problem on the tanks in the boat you surveyed for me?"

If he's giving you an old story about "tanks should only last 20 years" and can show you no evidence of corrosion, decay, etc. then I'd get on with the program until you see or smell gasoline in the bilge. In 20+ years of boating in Florida in boats over 40' the only boats I have ever seen need to have aluminum tanks replaced were those whose tanks sat in water. Sea Ray DA and EC tanks are outboard of the secondary stringers positioned along the hull where the only water they see is what you spray on then when you wash the engine room.
 
My tanks are 25 years old and have no sign of problems. The difference for me maybe that my tanks are under the salon floor well above the bilge floor where they stay dry. I have to agree with others, if it ain't broke, don't fix it!
 
Hi,

I have a 1989 340 Sundancer which has the anti syphone valve located in the pickup tube, which is not functioning properly. Does anyone know how to remove them?

Peter :smt089

1989 340 Sundancer
Twin 7.4 Inboards w/ vdrives
Danvers, MA
 
:smt021 my tank looked good till the day I pulled it and down inside she was bad!!! given the types of fuel stainless tank was the choice.:thumbsup:
 
Peter Frankfort said:
Hi,

I have a 1989 340 Sundancer which has the anti syphone valve located in the pickup tube, which is not functioning properly. Does anyone know how to remove them?

Peter
1989 340 Sundancer
Twin 7.4 Inboards w/ vdrives
Danvers, MA
Click to expand...
Peter,
The access is located in your aft cabin Under the window at the floor level there is a carpeted block about three feet long, mounted on an angle. Remove the two screws from the end brackets, carefully with a razor knife score the silicone which covers the edges. In front of the block is a molding, which I did not remove, I just tilted the whole thing forward.
There you will find the location of the top of the fuel tanks, pickup tube connection, and fuel senders. I just replaced the Port tank sender last week. I did not remove the pick up line, maybe the valve is inside the fitting protruding from the top of the tank. It looks like a male thread, and the fuel line screws on to it. Don't know? My boat is an 1988, maybe it don't have it? Please let me know more about it.:huh:
 
We looked at a 320 DA with a leak in one tank. Was told if we purchased the boat, to replace both tanks, and that it wold be about $12000 to do it.. We bought another boat....
 
Other than water being trapped against the tank, one of the other major causes of failure is the use of rubber strips under the tank as well as behind the tie-down straps. Rubber contains carbon, which will corrode aluminum.
The tanks on my boat were replaced six years ago and have what seems to be rubber strips behind the straps, but since the tanks are epoxy coated there won't be an issue.

But if you see rubber strips on a bare aluminum tank-beware.
 
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