Help needed to test SS crusie tank

[fender22]

Guys, when I bought my boat it came with a 90l underfloor tank, as well as a plastic 70L tank. The guy I bought it off said he didn't use the u/f tank because in his opinion the outlets are at the wrong end of the boat (at the rear).

His opinion was because the breather, fuel outlet and fill pipes where at the rear of the tank, and pointing towards the rear of the boat, as the nose lifted the tank would tilt on an angle and the fuel would run out of the lines and out the breather hole (the breather hole is higher than the outlet pipe).

Didn't sound right to me and as it turned out not a lot else I was told has turned out to be right either!

I'm not sure if it's a custom made job? It's SS and looks well made but has no brand on it. I have a 18.7' vickers easy rider and the well looks like it was made when the boat was and the tank fits properly so I'd say it was an original factory fit. How are these things set up inside? Do the pipes just weld straight onto where they join the outside of the tank or do they continue on to the front of the tank or down low in the tank? My other issue is before I use it would like to make sure it wasn't full of muck but doesn't look like it has an inspection plate to look in and the big filler pipe is welded on the end and you can't see anything from that. I took it to the boat mechanic and asked them to test it for me but all they could suggest was to fill it with fuel and I don't want to find out it has a leak after putting $100 bucks worth of fuel in it! Any suggestions or help appreciated

[station-rat]

Don't know how it would be plumbed internally, but a radiator shop would test it for you
Station-rat

[STUIE63]

I would have thought that there would be a pickup near or at the bottom of the tank.
why not fill it up with water to test for leaks.
the other one I have heard is to put compressed air in the tank and use spray and wipe to find any leaks just don't pump it up to alot of pressure
Stuie

[Dan5]

Mate i used to build and repair tank's,the fuel pickup should by right's be at the stern end of your tank and reach down to the lowest part the breather should be at the bow end close to the filler and penetrate about 20mm inside.To do a simple pressure test seal off your breather,filler and pickup and put some compressed air in but only a little say .5-1 psi max and go over with detergent in a bottle looking for bubbles.The tank should also be baffled in side.Dan........

[Vindicator]

Another way is to pump it up with air and screw a pressure guage into on of the outlets. Watch the guage and if it drops, start looking for leaks.

Cheers
Kezza

[fender22]

Thanks Dan, that all makes sense. The outlet, filler pipe and breather pipes are all at the rear of the tank though? I was wondering if even though the breather pipe was at the rear if maybe that pipe extended into the tank to the front maybe? I have a mate who is a sheet metal worker and he's made a few and reckoned that the ones he made had the breathers at the back and they were fine. His theory was as most boats sit nose heavy on the trailer (when you would be filling it up) if the breather was on the front you would get run back then anyway so whether the breather is on the back or the front at some point both has it's drawbacks.. He reckons as the long as the tank has baffles and the breather outlet on the boat is well above the tank, should be ok?

The main filler pipe (about 1 1/2") is also on the rear of the boat and it is connected by a thick pipe to the filler cap inlet on the gunwhale. Ant dramas with that at the rear?

[Chimo]

Hi Fender22

You have had plenty of input re testing the tank.

I will add a suggestion that you take the tank out and do what ever tests you need to give you confidence to use it for fuel.

When you re-instal it though make sure it is seated on thin teflon strips on both sides and probably the middle too.

I suggest this as I have previously had to replace a 250 lt ss tank that sat on a flat fibreglass bed without the teflon strips (they forgot to put them in is all I can assume but with a little salty moisture under the tank, over a number of years pin holes developed. This only became obvious when ULP appeared in the bilge, not a good thing!

Re filling the tank, mine is a long thin thing too and all I do to make sure its full is drop the nose of the boat when filling and get heaps extra in as a result without any breather blowback which I can get out of both breathers if I try to get it full with the bow up.

If the thing doesn't leak just use it as the fuel in it will keep better too being in a cooler spot especially if you keep the tank full, don't use BP with ethanol and don't move the boat between uses.

Cheers
Chimo

[Spaniard_King]

Fender,

to test the breathers location simply lift the bow end so as it is above the filler pipe(may need to remove the tank from boat) comence filling the tank with water by just hanging a hose in the filler pipe.. if the water comes out the breather before you get the water flowing out the filler (tank say 75% full) then you could safely say the breather is located at the rear of the tank.. if no water flows out the breather before the tank is almost full then the breather is piped to the front of the tank

[fender22]

Guys I notice a few of you suggested filling the tank with water as a test which brings me to my next question as on pulling the tank out I've discovered it's 1/4 full of water! SOmeone obviously had the same idea and stuck a hose in it I'd say.

How do you thoroughly remove the water and dry the tank properly once every thing is ok? Tha tank has baffles etc and little places for the water to collect making emptying it out 100% difficult. I beleive even a few drops of water in your fuel can cause dramas?

[Chimo]

Hi Fender

I'm sure most, many ,some would / may agree that more often than we like to think there is some water in our fuels due to ? where we get it, condensation etc

While not knowing what motor and what pre filter you are running you should be able to deal with the little water left with your filter and for what its worth to you I add about 1% metho to my fuel from time to time to get water moving out of the tank and thru the system ie filter / water trap.

Some water does get trapped in the filter and I think some goes thu given the effect the metho has on it. So far so good with mine but I'll be interested to hear others thoughts too.

Cheers
Chimo

[finding_time]

I know it's a little of topic but a good fuel tank should have breathers at both the bow end and the aft end as sometimes you fill the tank with the bow facing down hill and sometimes with the bow up hill!

Ian

[Oh Gee]

Lots of good advise but be careful putting any presure in it especilly if its outside the boat. wouldent take much to expand it enough to make it a bugga to refit. If your looking for a low cost, low presure gauge for use with the detergent method, use a ballon.

G

[PADDLES]

be careful pressurising it, they're usually not designed to hold much pressure. my old signature had an optional long range tank which had a breather at both ends, the one for the front ran internally and actually was welded internally into the top of the filler tube.

[fender22]

A ballon is an awesome idea! Could blow enough pressure into it by mouth until the baloon blows up a bit and just watch if it deflates! (I can think of a hundred funny comments here!)

On pulling the tank out it was half full of water, god only knows why... so I may as well just fill it with water and see if it leaks, then an emtpty out and gallons of metho splooshed around in it to dry it!