Fuel Leak

[pjbink]

I wonder if Raiders can help out with this. I have a new aluminium underfloor fuel tank which leaks a little bit from the fuel outlet on top of the tank (when full). Note the oultlet is a seperate fitting. I have tried sealing it with a sealant called 'Stag' but it still finds a way out. I could try building up a seal with more Stag or perhaps Raiders could recommend a better product (maybe some sort of tape). Alternatively I could take it back for further welding around the join.

[Dreamtime]

Try CRC Minute Mend, or a similar Epoxy Cement

Edited August 18, 2008 by Mariner 31

[pjbink]

Thanks Mariner 31. Actually I think I have a tube of a similar product in my workshop.

Have you tried it with fuel though? The product description doesn't mention it in this application. Given the high volatility of fuel I am worried how effective a seal it would give.

[pelican]

Is it a screw on fitting or is it a screw down fitting with a flat flang"?. Stag is only good for fine tolerance like a screw in fitting ( ie coat the threads). A gasket is what would be required with stag either side for wider tolerance like a flange mount. Expensive but flat nitrile sheet ( fuel proof oring material) would be suitable if surfaces were reasonable tolerances and there were enough screws to apply tension. Fuel prook gasket sheet is the cheaper option. Most fuel fittings come with suitable gaskets of suggest material. I hope it it a actual fuel fitting. A lot of fuel fittings don't seal very well as they are designed to be at a "no pressure" zone at the top of a fuel filler tube not on the top of a tank in the floor. Are you 100% it is the flange leaking not the cap? Do a search of race tank fittings and you will see some that seal with orings for the caps but must are weld on as there is always a concern with ally corroding at the flange and losing it's ability to seal.

Ps if it is new I hope the people that made it have a solution for you.

Edited August 18, 2008 by pelican

[Dreamtime]

Hi billfisher, my engineers use it frequently on applications involving fuels and oils.

I would however recommend that you give the surface a good clean with a solvent cleaner, then rough it up with a wire brush or some 40 grit sandpaper.

Ensure it is fully cured prior to contact with petrol. Once cured, it sets pretty well like steel.

Maybe you could try CRC's website for further details.

Sorry I can't be of better information.

Cheers

[pjbink]

Thanks for your input Pelican and Mariner 31. it looks like the Stag is not going to work. I think the epoxy might be worth a try or I could take the tank back and get them to weld around the fuel conector.

[pelican]

Most epoxy is very brittle once cured but good for a quick temporary fix. Some of the metal epoxies have a copper base and cause long term corrosion with ally when exposed to salt water. If it is possible I'd have it welded and make sure you are getting a airtight and fuel tight fitting as you should have a breather mounted higher to let air into the tank. Nothing worse than fuel and vapour in a bilge.

Edited August 26, 2008 by pelican

[Guest]

Do not take any risks with fuel tanks and vapours.

Have the tank removed and fixed correctly and you will sleep a whole lot better at night.

The last thing you want is an explosion aboard your vessel

Cheers Stewy

[novice]

I had a fuel leak too. I was losing about 20lts every ful tank. It turned out be a missing or degraded gasket under the sender.

I took the boat to my marine mechanic in wetherill park, and he fixed it.Cost bugger all, and I know it's done properly. He prssure tested the tank, and all good now.

Perhaps you too should consider having a preofessional have a look ..... The risk is far greater that the outlay for a quality repair.

Taps.

[pjbink]

I had a fuel leak too. I was losing about 20lts every ful tank. It turned out be a missing or degraded gasket under the sender.

I took the boat to my marine mechanic in wetherill park, and he fixed it.Cost bugger all, and I know it's done properly. He prssure tested the tank, and all good now.

Perhaps you too should consider having a preofessional have a look ..... The risk is far greater that the outlay for a quality repair.

Taps.

Nothing like losing 20L, Taps. Just a bit of seepage when the tank is full (around the fuel outlet). I'll take it back to the people who made it and see if they can weld around the outlet.

PS: I didn't bother with fitting a sender to avoid problems like this!