Gas tank leaking
- Thread starter srizell938
- Start date
More than likely it is leaking from the bottom. 40 years ago, not as much was known about the effects of aluminum tanks and the way they were secured. Often the tanks would be in contact with wood or rubber strips on the bottom. Both would cause corrosion over time. Even rubber used between metal strapping and the tank could cause issues. It certainly could be something else, but that's the most likely cause.
I don't know if you have decent access to remove it through the cabin, but I suspect the way to do it would be to remove the engines. But don't worry... for anyone that has some experience, it's really not that bad of a job.
I don't know if you have decent access to remove it through the cabin, but I suspect the way to do it would be to remove the engines. But don't worry... for anyone that has some experience, it's really not that bad of a job.
srizell938
New Member
Thanks. I’ve done several repairs since I’ve bought it. But just kind of throwing my hands up at this one lol. Had it on the water for one weekend and this happens lol
I hear 'ya. It can be a little disheartening at times and and feels like it will never stop. Obviously it's a 40 year old boat so it's somewhat to be expected, but it doesn't make it feel any better knowing that.
Thornton69
Well-Known Member
- Sep 15, 2014
- 1,149
- Boat Info
- 1981 245 SDC
2021 Solar 420
- Engines
- '97 5.7 Bravo 2
'20 Merc 25 EFI Jet
Our 245 is a custom build from an '80 270SDB platform. It is currently down for stringer replacement. Hope you don't have the same problem but it appears you do looking at the last photo. We pulled the tank for the stringer repair. Was actually more difficult than expected. Our engine was already out but it wasn't required for the fuel tank removal due to the high rear deck. The tank has to go forward into the cabin and up to clear it. Also, ours didn't fit thru the door without removing the whole frame along with the panels between it and the rear cabin walls.
Thornton69
Well-Known Member
- Sep 15, 2014
- 1,149
- Boat Info
- 1981 245 SDC
2021 Solar 420
- Engines
- '97 5.7 Bravo 2
'20 Merc 25 EFI Jet
Looking again at your pics, you can probably turn your tank on it's side and pass it thru the door. Ours was modified to hold 100 gal and that wasn't an option for us. Attached a pic of it and also a drawing of the 270 from our manual in the event you were interested.
srizell938
New Member
Thanks for the info. I love working on my own stuff, and was expecting things to be broken considering the age of the boat. I gave 5 grand for it, including the trailer. So I knew it probably needed some work. I usually spend a lot of time on the internet researching things to try and figure it out. But I can’t seem to find much about this problem lol. Being new to boats like these, I just didn’t know where to start. But I’ll figure it out. Hopefully before summer
- May 14, 2008
- 3,540
- Boat Info
- 1988 390 EC
- Engines
- 454 Mercruiser Gassers
Short of pulling an engine, you could always take it out through the side hull and have it re-glassed after the new tank goes back in. With the tank out, it would give you an opportunity to shine up that portion of the ER.
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Stee6043
Well-Known Member
Leaking fuel is a bummer. It's not like a leaking fresh water tank where you can live with it for a summer if needed.
One way to find out whether or not the leak is at the bottom is to drain the tanks to certain points and see if you can make the leak stop along the way. I'm not sure this changes your potential repair path, however...
One way to find out whether or not the leak is at the bottom is to drain the tanks to certain points and see if you can make the leak stop along the way. I'm not sure this changes your potential repair path, however...
Little Ducky
Well-Known Member
- Jun 5, 2017
- 2,654
- Boat Info
- 1998 290 Sundancer
- Engines
- Twin EFI 5.0L w/Alphas
Kohler 4kW
Just to be sure there is not a hole in the vent line or tank fill line I would see about doing a pressure or hydro test and see if it holds...... or even a smoke test and see if you can identify the leak.
This might save you some headache and it be a hose or sender gasket issue.
Are you seeing liquid fuel or are you smelling vapors?
This might save you some headache and it be a hose or sender gasket issue.
Are you seeing liquid fuel or are you smelling vapors?
srizell938
New Member
Yes. There is fuel filling up the engine compartment. I haven’t had the boat very long. First time I took it out I only put 30 gallons in it and didn’t see any issues. This time I was going to fill it up completely. Put 56 gallons in it and it started leaking out the drain plug at the rear of the boat
SCORPIO
Well-Known Member
If it's not a leaking hose or fitting, then it's probably crevice corrosion. Moisture gets trapped between the aluminum tank and the straps or the platform it's sitting on and causes pitting corrosion of the aluminum. Eventually those pits penetrate the tank and you have a leak.
After you're sure the leak is the tank itself, drain the tank, CAREFULLY! and remove, probably by pulling engine(s). Get detailed dimensions and have a tank service build you a new tank. Boating rags are full of tank fabricators. An internet search would yield results near you no doubt. While the engines and tank are out, power wash and paint the bilge, it will look and smell a lot better and it will fill the few weeks while the tank is being built.
After you're sure the leak is the tank itself, drain the tank, CAREFULLY! and remove, probably by pulling engine(s). Get detailed dimensions and have a tank service build you a new tank. Boating rags are full of tank fabricators. An internet search would yield results near you no doubt. While the engines and tank are out, power wash and paint the bilge, it will look and smell a lot better and it will fill the few weeks while the tank is being built.
Adding a little more info for you... Scorp used the term 'crevice corrosion' which is totally correct, but may be a misleading term to someone unfamilar with that. In essence, aluminum is a fine material to use for your new tank. It's the proper installation that matters... air circulation being the key. As long as there is air circulation, the aluminum will self protect itself. When certain materials are used, they cause moisture to stay in contact with the aluminum (no air circ)... and we're back to CC.
I briefly mentioned it above, but rubber, itself, is bad as it contains carbon with will also cause corrosion to Al.
There's any number of sources you can google to find proper installation techniques. However, the jist of it is that you will install FRP strips to the bottom of the tank - COMPLETELY covering the contact area with 5200 and fairing the edge to avoid moisture collection. The strips elevate the tank off the bilge floor, again for air circ.
The tank should also not be so big that it fits tightly to a bulkhead (more moisture collection). Always leave an air gap. FRP blocks or angles can be used to secure the tank.
I suppose this goes without saying, but just in case... DO NOT OPERATE the boat until this gets fixed. You don't want to be a statistic!
I briefly mentioned it above, but rubber, itself, is bad as it contains carbon with will also cause corrosion to Al.
There's any number of sources you can google to find proper installation techniques. However, the jist of it is that you will install FRP strips to the bottom of the tank - COMPLETELY covering the contact area with 5200 and fairing the edge to avoid moisture collection. The strips elevate the tank off the bilge floor, again for air circ.
The tank should also not be so big that it fits tightly to a bulkhead (more moisture collection). Always leave an air gap. FRP blocks or angles can be used to secure the tank.
I suppose this goes without saying, but just in case... DO NOT OPERATE the boat until this gets fixed. You don't want to be a statistic!
Thornton69
Well-Known Member
- Sep 15, 2014
- 1,149
- Boat Info
- 1981 245 SDC
2021 Solar 420
- Engines
- '97 5.7 Bravo 2
'20 Merc 25 EFI Jet
Should the aluminum tanks be coated or have a some kind of primer applied to them to help protect from corrosion? The one in my boat had been, but did have corrosion starting where moisture was trapped in a couple points of contact on the bottom.
SCORPIO
Well-Known Member
On my last boat, I had a new aluminum tank made with solid blocks of aluminum welded to the bottom to allow tank to have airspace beneath it. I had brackets welded on to attach the tank to the sides of the compartment. Also, it was Alodyne prepped, etched and painted with Awlgrip. It was still perfect after 10 years. BTW I had the tank built out of MUCH thicker aluminum plates than factory, suitable for offshore performance.
Thornton69
Well-Known Member
- Sep 15, 2014
- 1,149
- Boat Info
- 1981 245 SDC
2021 Solar 420
- Engines
- '97 5.7 Bravo 2
'20 Merc 25 EFI Jet
Well that's sounds like another boat buck! Thanks for sharing. Since I'm planning to move my rear cabin wall anyway, maybe a new larger tank is the smartest way to go. Did you happen to have any pics of your tank? I like the idea of the blocks for (ventilation) spacing.
Bt Doctur
Well-Known Member
Tough nut there
Pull the engines, remove the bulkhead pull tank rearward to remove
Pull the engines, remove the bulkhead pull tank rearward to remove
Coal Tar epoxy is another coating that has been used for years and years.
I've 'heard' of people using truck bed liner - I have no idea how it's lengevity is in this application. But I applied it to a 35' aluminum dock ramp (salt water environment) about 4 years ago for traction. It's just starting to wear in some places so I'll give it another coat. Granted, this gets abused from foot traffic, where a fuel tank would not.
Interesting idea on having aluminum blocks welded on the bottom.
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SCORPIO
Well-Known Member
It was just a rectangular 100 gal center tank, nothing fancy. The guys that built it for me also built the tanks for Ocean Yacht and Pacemaker, quality work.
srizell938
New Member
Thanks again for all the info.