Fuel tank replacement

Unreel

Well-Known Member
Well it looks like my built in tank in my 2470 has a leak, so will be looking to have it pulled and replaced. Anyone around Nanaimo or the central island that builds aluminum tanks and or does installs? Luckily theres a removable hatch over the tank but the great pursuit engineers decided to make it not quite long enough to pull the tank so have to either cut part of the deck or cut up the tank to remove it.
 
Well it looks like my built in tank in my 2470 has a leak, so will be looking to have it pulled and replaced. Anyone around Nanaimo or the central island that builds aluminum tanks and or does installs? Luckily theres a removable hatch over the tank but the great pursuit engineers decided to make it not quite long enough to pull the tank so have to either cut part of the deck or cut up the tank to remove it.
 
Anyone know of a place or person that can pressure test the tank in the boat? Called 2 marine shops in nanaimo and they had no clue, no surprise there.
 
it’s not all that hard to do if you can get at your hoses easily enough? Have you pulled the deck hatch up yet. the fill is usually the most akward I have a wood plug for that and hose clamp if the deck fitting is leaking use the vent hose to attach a tee that has one end 5/8 barb the others will be a shraeder valve and low pressure gauge so youll need some bushings etc get creative at Home Depot shut the valve at the tank off that goes to your motor/separators use a bike pump and on the shraeder and pump it up to 3psi. Take some dawn dish soap or similar in a squirt bottle and spray every fitting to check for leaks if there aren’t any let the tank sit overnight your going to loose a little pressure probably from temp change but not much.

This gauge will work https://www.amazon.ca/Winters-Econo...ocphy=9001572&hvtargid=pla-449704203760&psc=1
Shraeder valves

Edit: should add battery switch should be off during the test pretty obvious but easily overlooked.
 
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it’s not all that hard to do if you can get at your hoses easily enough? Have you pulled the deck hatch up yet. the fill is usually the most akward I have a wood plug for that and hose clamp if the deck fitting is leaking use the vent hose to attach a tee that has one end 5/8 barb the others will be a shraeder valve and low pressure gauge so youll need some bushings etc get creative at Home Depot shut the valve at the tank off that goes to your motor/separators use a bike pump and on the shraeder and pump it up to 3psi. Take some dawn dish soap or similar in a squirt bottle and spray every fitting to check for leaks if there aren’t any let the tank sit overnight your going to loose a little pressure probably from temp change but not much.

This gauge will work https://www.amazon.ca/Winters-Econo...ocphy=9001572&hvtargid=pla-449704203760&psc=1
Shraeder valves

Edit: should add battery switch should be off during the test pretty obvious but easily overlooked.
Thanks, i was actually down at the boat for a while with a homemade tester trying to get it to work. I used this https://www.canadiantire.ca/en/pdp/...-vacuum-pressure-tester-0251039p.html?loc=plp and put it on a tee, with one hose going into a piece of rubber i'd stuffed in the fill neck and the other one going to a hand pump. I put tape over the tank vent on the hull and closed the fuel line shutoffs but i couldn't get it to build pressure to register on that gauge. I think the tape over the vent wasn't able to hold much pressure. But when i would pull the piece out of the fill neck or disconnect the pump i would get air rushing back out the filler, which i dont think would happen if i had a good sized whole somewhere. The fun continues
 
Just stuff a rag in the fill etc, pinch off the vent hose with vise grips and something flat to stick in the jaw. Use the fuel lines the pressure input line. Don't go top much pressure though. I've watched guys do this and crack old fuel tanks doing pressure testing.
 
you would be surprised how much 3psi will actually inflate the tank you probably had 1/2# in there or less to do the test properly you need to cap things off a rag etc is just going to leak slowly and won’t tell you anything. When I test new tanks you can actually see the aluminum 3/16 and baffled bowing out. If you want to be cautious go to 1.5 mark your gauge and give it 12hrs. I say to wait this long because a pin hole will take time to bleed out and if none of the hoses or fittings are leaking the tank is the culprit. Soap up the sending unit area as well those screws/gaskets are often leaking during a test.
 
you would be surprised how much 3psi will actually inflate the tank you probably had 1/2# in there or less to do the test properly you need to cap things off a rag etc is just going to leak slowly and won’t tell you anything. When I test new tanks you can actually see the aluminum 3/16 and baffled bowing out. If you want to be cautious go to 1.5 mark your gauge and give it 12hrs. I say to wait this long because a pin hole will take time to bleed out and if none of the hoses or fittings are leaking the tank is the culprit. Soap up the sending unit area as well those screws/gaskets are often leaking during a test.
So to sum things up, twice now in the last 4 months I’ve come down to the boat and had a fuel smell in the cuddy. The first time it wasn’t super strong but could tell when I opened the cuddy, then opened the front bilge compartment where it smelled stronger. I wasn’t 100% sure it was gas as there seamed to be oil in the bilge too which was super odd. This time last week when I came down to the boat I could smell it when I got on the boat and very strongly in the cuddy. There was clearly fuel in the bilge water along with what looked like a black oil. In between this time I’ve never smelled any fuel or had it in the bilge and I’m on the boat multiple times a week and always check the bilges. I’ve used the boat a number of times, only had about 1/4 tank and all the connections, filters etc are dry. In fact there is no fuel smell in the rear bilge, or when I open the inspection ports over the tank. The last time it happened I was using the boat the day before. But no smell or anything until I came down the next day and found fuel in the front bilge. Since then I cleaned it up, waited a couple days, no smell, took the boat out, got up on plane a bunch of times, did a number of sharp turns etc. Zero smell or anything after or days later. I’m perplexed as to how just 2 random times this has happened but in between I’ve had no issues.
 
that is a little bit odd that it hasn’t been consistent but could be a small leak usually corrosion along one of the weld seams. get the test setup properly on the tank if it passes then your all good there and can move along to checking the rest of the system.
 
I had the same problem in a boat that I sold to someone,I was honest with him that I could smell fuel at times but couldn't find a source or even fuel in the bilge.I filled the tank and inspected everywhere I could and found nothing.He eventually found a cracked seam and had it fixed or replaced.
 
I would replace all hoses first. And redo all fittings. Low hanging fruit first. I am now expert but I would do my leak down test with a Magnahelic that measures inches of water column. See if you can find an HVAC person to borrow one from.they measure small pressure differences much better than anything else.
 
So I got my pressure tester built and tried it out. Does this look like it would be accurate? I put the hose in the tank vent and sealed it up. Glued on a valve stem on the other end. Used a bicycle pump which took a while to build pressure. I got it up to just under 1psi when I heard a thud from the tank, assuming one of the walls being flexed out. So that was enough to scare me into stopping. I didn’t want to leave it overnight but I let it sit for a few hours and didn’t see any visible drop on the gauge. Also sprayed the connections on the top of the tank and no bubbles. I figure if that’s enough pressure to flex one of the side walls, would it not be enough to show a leak?
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Thud would be one of the walls expanding for sure if your able to build pressure and had no leaks over a couple hours you should be ok. the longer you can leave the test on the better but if your confident in your work soaping everything up and there is no fuel in the locations where you found it after the test your probably fine. The mystery continues.. check the fuel water separators, and hoses.
 
All fuel tanks for a Commercial Vessel are to be tested to a pressure of 24.525kPa or 2.5m water or 3.6psi. The pressure for the test may be measured by means of a Liquid Manometer or a Pressure Gauge. When a pressure gauge is used, care must be taken to prevent the over-pressuring of the compartment.
 
So I got my pressure tester built and tried it out. Does this look like it would be accurate? I put the hose in the tank vent and sealed it up. Glued on a valve stem on the other end. Used a bicycle pump which took a while to build pressure. I got it up to just under 1psi when I heard a thud from the tank, assuming one of the walls being flexed out. So that was enough to scare me into stopping. I didn’t want to leave it overnight but I let it sit for a few hours and didn’t see any visible drop on the gauge. Also sprayed the connections on the top of the tank and no bubbles. I figure if that’s enough pressure to flex one of the side walls, would it not be enough to show a leak?
View attachment 88828View attachment 88829

The time it takes to show a leak with a compressed air test has to do with the volume of air in the tank and how big the leak is.

If the tank has very little fuel and a large volume of compressed air in it, a small leak may take a long time to show pressure drop on the gauge.

To get the fastest drop on the gauge, the tank needs to be full. Think an air receiver on a compressor. Takes a while for the pressure to bleed off when you open a valve. Same here. You want as small a volume of air as possible otherwise you will have to wait a while. How long, not sure, depends on the leak size and the volume of air.

Typically I've seen 24 to 72 hours with a stable pressure as common practice to confirm no leaks in industrial settings.
 
All fuel tanks for a Commercial Vessel are to be tested to a pressure of 24.525kPa or 2.5m water or 3.6psi. The pressure for the test may be measured by means of a Liquid Manometer or a Pressure Gauge. When a pressure gauge is used, care must be taken to prevent the over-pressuring of the compartment.
Where did you find this information? Not doubting it but I’ve only ever seen transport Canada defer to abyc standards for testing. I have done a number of tests on tanks and would be very impressed to see a fuel sender hold more than 3psi. I frequently have to remove them and put a dummy plate in place to get the test to pass at 3psi sometimes they do but more often they are leaking from the unit itself. totally agree about the test time for air testing and it’s much better to have the tank isolated out of the boat where you can soap all the seams etc. I wouldn’t want to fill a suspected leaking tank full of fuel though before confirming it’s good..
 
My Bad. I thought it was 3lbs and grabbed this web capture but it's for automotive. After digging some more, I found this.
"Since January 1 of 2011, CARB and the EPA have required that all portable fuel systems manufactured for use with outboard motors follow a near-zero-emissions policy. EPA certified tanks are required to hold a minimum of 5psi of internal pressure generated by ambient temperature changes or warming from the sun. Before the 2011 EPA mandates went into effect, fuel tanks generally included a fuel fill cap with a manually operated vent that allowed users to release vapor pressure in the tank to the atmosphere. Opening the vent and leaving it open also prevented a vacuum from developing in the tank that can stall an engine. When the vent was left in the open position, the tank became an “open system” that continuously released fuel vapors to the environment. To meet the new regulations, EPA certified tanks do not include this feature."

Personally, I always thought 3 was more than enough if it held it overnight. I always found the leaks were usually around the fitting.
 
Think that’s just for portable day tanks. permanently installed tanks fall under a different category. That I am aware of transport canada references ABYC-h24 for gasoline tanks and h33 for diesel. for anyone interested you can google the documents and read through them.
 
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