fuel tanks

mr elevman · Post by **mr elevman** » Fri Dec 26, 2008 4:38 pm

my tanks are full of gonk 50 gallon hot diped galv. thay dont leak i found a place that will psi test then clean them the tanks are 36 years old should i replace or clean and reinstall i found plastic tanks 50 gallon that will fit or clean and replace only to have to replace in the future

prowlersfish · Post by **prowlersfish** » Fri Dec 26, 2008 5:35 pm

galv tanks , get rid of them

ready123 · Post by **ready123** » Fri Dec 26, 2008 7:30 pm

prowlersfish wrote:galv tanks , get rid of them

Is it in fact as simple as that? Why do you have such strong feelings?
Are you happier with aluminium?

I think more to the question here is what has been the cause of the sludge buildup? Is it likely to repeat with any replacement. What is the fuel being used?
I don't see that the tanks being galvanized is the root cause of anything.

Does he really need to go to the expense of removing them to clean the sludge? Are they really 'full' of sludge or just enough to plug the bottom of the pickups?
I think there are more questions than answers here at this point in time.....

prowlersfish · Post by **prowlersfish** » Fri Dec 26, 2008 9:09 pm

Yes I am happier with aluminium but then you can't use galvanized tanks with diesels . but thats not the reason in his case .

There is no perfect tank . the proplem with galvanized tanks when the start to rust inside and it can end up the fuel system and and I have seen sevral that the bottom just fell apart . galvanized tanks havent been used in years on boats , and I am sure by good resone . any boat that still has them is in borrowed time IMO .

The posting question was would you replace galvanized tanks with plastic or clean them out . my answer still is replace them you start cleaning them and rust starts coming apart next thing you know you got a big hole. I rember getting readt to go fishing the owner when to stick the tank with his stick ( about the size of a broom stick ) he droped it in the tank like he alwas did . when the stick when out of sight we had a sick felling. the stick when thru the bottom of tank .

Being they are 36 years old I would replace them no matter what they are . as far as the sluge that could be from 36 years of use or some bad fuel . ether way the proplem will fixed and make sure you buy good fuel

mr elevman · Post by **mr elevman** » Fri Dec 26, 2008 9:37 pm

boat sat for 5 years i had the tanks pumped out and this is the first time thay had eathanol in them withch caused all the built up whatever to dislodge and settel on the bottom i was clogging a seperator in 1-2 hrs i pulled the sending unit and used a mini mag light and a pice of copper tubing to examin the bottom as you toutch it it would poof big cloud i think im going to save myself the headach latter and just go with new tanks

ready123 · Post by **ready123** » Fri Dec 26, 2008 9:49 pm

prowlersfish wrote:Yes I am happier with aluminium but then you can't use galvanized tanks with diesels .

To be strictly correct cannot use both side galvanized with diesel fuel, outside only works fine.

prowlersfish · Post by **prowlersfish** » Fri Dec 26, 2008 9:58 pm

ready123 wrote:
prowlersfish wrote:Yes I am happier with aluminium but then you can't use galvanized tanks with diesels .
To be strictly correct cannot use both side galvanized with diesel fuel, outside only works fine.

true if you could find (or want )one kind of outdated IMO

galvanized have a expeted life of 10 years or so

http://www.uscgboating.org/recalls/pdfs/bscscan64d.pdf

ready123 · Post by **ready123** » Fri Dec 26, 2008 10:41 pm

mr elevman wrote:boat sat for 5 years i had the tanks pumped out and this is the first time thay had eathanol in them withch caused all the built up whatever to dislodge and settel on the bottom i was clogging a seperator in 1-2 hrs i pulled the sending unit and used a mini mag light and a pice of copper tubing to examin the bottom as you toutch it it would poof big cloud i think im going to save myself the headach latter and just go with new tanks

Or you can consider that ethanol effect as the cleaning agent. You could then vacuum the solids out through any one of the access holes. Once that was done I would recommend the use of a non ethanol fuel supply.

Some interesting reading on the subject of ethanol in marine fuel:
http://www.cymagazine.ca/index.php/Home ... -Fuel.html

prowlersfish · Post by **prowlersfish** » Fri Dec 26, 2008 11:01 pm

non ethanol fuel supply ??? we are down here in the land of the EPA
its almost imposable to find non ethanol fuel . are you all dealing with low sulpher diesel and ulsf diesel up there .

ready123 · Post by **ready123** » Fri Dec 26, 2008 11:12 pm

prowlersfish wrote:non ethanol fuel supply ??? we are down here in the land of the EPA
its almost imposable to find non ethanol fuel . are you all dealing with low sulpher diesel and ulsf diesel up there .

Our marine fuel supply is non ethanol and super grade 91 octane.
Can't comment on marine diesel as I'm a gas hog.

though I do believe we have been ultra low sulphur diesel since 2006.

prowlersfish · Post by **prowlersfish** » Fri Dec 26, 2008 11:25 pm

we have low sulpher at the dock and ULSD on the road . 10% ethanol on the road and at most all fuel docks .

ready123 · Post by **ready123** » Sat Dec 27, 2008 12:34 am

prowlersfish wrote:we have low sulpher at the dock and ULSD on the road . 10% ethanol on the road and at most all fuel docks .

That must play havoc with the longevity of 2 cycle outboards. I can see why there are so many class action suits in play down there.

A Yamaha dealer friend of mine had some major 4 cycle failures that they put down to the use of a regular gas brand up here that had close to 20% ethanol.... they say min 10%, maybe they should quote max too.

Shell seems to be the main supplier up here that is maintaining a zero ethanol level in marine fuel. A number of marinas switched to other suppliers when Shell went to Super grade at all their marinas due to ethanol concerns when they started putting it in the mid grades too.

Seems that those marinas were only motivated by selling price and were ignorant of the effects of ethanol in a marine application.

prowlersfish · Post by **prowlersfish** » Sat Dec 27, 2008 8:55 am

"That must play havoc with the longevity of 2 cycle outboards"

Just wounder why you said that , I did notice when I bought some gas dryer it said not to use with 2 cycle engines on one and on another said it was ok for 2 cycle same brand but diffrent price and diffrent type alcohol
makes you wonder

ready123 · Post by **ready123** » Sat Dec 27, 2008 12:36 pm

prowlersfish wrote:"That must play havoc with the longevity of 2 cycle outboards"
Just wounder why you said that ,

Ethanol attracts water even from the air (marine fuel tanks are not sealed like cars and so the tank vent can give a continuous supply of moist air) it also does not mix well with oil and tends to break down it's lubricating ability due to the water content... so since in a two stroke the oil for lubrication is mixed with ethanol/gas it tends to not give good lubrication at higher revs and will tend to cause earlier engine/bearing/piston ring failure.
To quote the experts:
"Water as a separate phase, can have a major effect on two-stroke outboard engines because when the ethanol bonds with the water and drops out of the gasoline, the effective octane rating is decreased. Also, in the case of two-stroke engines, this water-ethanol phase will compete with the blended oil for bonding to the metal engine parts. Therefore, the engine will not have enough lubrication and engine damage may result.

In the case of four-stroke gasoline engines, the water-ethanol phase may combust in the engine. This combustion can be damaging to the engine because the water ethanol phase creates a leaner combustion mixture (i.e., air to fuel ratio is higher than ideal). Leaner mixtures tend to combust at higher temperatures and can damage engines, particularly those without sensors to calibrate air to fuel ratios. "

randyp · Post by **randyp** » Tue Dec 30, 2008 10:30 am

I have experience with 30+ year old galvanized gas tanks - they were what the 77 F26 came equipped with as original. Mine started rusting on the inside and the resulting diluted/dissolved gunk wrecked havoc with fuel delivery/system. The other risk was rust-through - maybe not as big an issue in fresh water (my location) but salt water would most likely accelerate the process - rusting through and creating a raw-gas leak into the bilge.....

I replaced the galvanized tank with a cross-linked polyethylene tank (plastic) in 2000 and have not had a problem with fuel contamination at all.

Ethanol in the fuel will create a problem if it's left in the tank too long....water separation. My marina/fuel source will have E10 next season for the fiirst time (damn!) so I will be very careful to run the fuel on a regular basis. Right now it's in storage with a tank full of good ol 89 octane E-0. I'm not looking forward to the world of E10, but I'm sooo glad I don't have galvanized tanks anymore.