Fuel tank repair question - E31

[David Vaughn]

So we discovered a very slight leak in our original aluminum diesel tank. Just a bit of seepage in the lowest corner. Fortunately E31s came from the factory with an access port so, I was able to drain the tank, clean it reasonably well, and after some new boat yoga poses, patch it with some JB Weld fuel tank seal. So far so good.

After adding a few gallons of clean fuel, I thought, okay now there will be air in the fuel line, since the pickup tube was empty. But then it occurred to me that the highest point of the fuel pickup line is above the tank and then runs downhill to the primary filter and fuel pump. That fuel has nowhere to go. So I decided to crank the engine and see if any air bubbles would work their way down. Ran it for a total of about 15 minutes and it ran fine.

Have I missed something? Should it run longer to be sure there’s no air before I set off to the haul out yard tomorrow? Would really prefer to not have to bleed it in the middle of the river halfway to my destination.

 

[JSM]

Sounds like you should be good after 15 minutes. See what happens at higher rpms and bleed the system if need be. If you can get the tank out have the leak welded up so that you never have to deal with it again.

 

[Prairie Schooner]

David,
What engine do you have?* Our Universal has a bleed valve at the injector pump which puts air into the fuel return circuit. That's done the job well for us. So far I've never needed to bleed at the injectors.
Jeff

* Many people will put their engine model in their signature line. I find it helps me get more applicable responses.

 

[David Vaughn]

Hi Jeff

Yeah I should have mentioned that. It’s a Yanmar 2QM15. As far as I know it’s original. I’ll pull out the manual and see if it’s set up the way yours is.

The good news is after 7 hours of uneventful motoring, I reached my destination. At the moment I don’t fully understand where the air that had to be in the vertical portion of the fuel pickup line went, but it didn’t cause me any issues.

 

[DTrail808]

So we discovered a very slight leak in our original aluminum diesel tank. Just a bit of seepage in the lowest corner. Fortunately E31s came from the factory with an access port so, I was able to drain the tank, clean it reasonably well, and after some new boat yoga poses, patch it with some JB Weld fuel tank seal. So far so good.

After adding a few gallons of clean fuel, I thought, okay now there will be air in the fuel line, since the pickup tube was empty. But then it occurred to me that the highest point of the fuel pickup line is above the tank and then runs downhill to the primary filter and fuel pump. That fuel has nowhere to go. So I decided to crank the engine and see if any air bubbles would work their way down. Ran it for a total of about 15 minutes and it ran fine.

Have I missed something? Should it run longer to be sure there’s no air before I set off to the haul out yard tomorrow? Would really prefer to not have to bleed it in the middle of the river halfway to my destination.

Didn't know this stuff existed. Having a fuel issue myself, but still hoping its not the tank but the lines and connectors themselves. Happy to hear of a patch that works if it's infact the aluminum.

 

[David Vaughn]

So far I’d say “recommend”. I left a 3M oil absorbing pad at the place it had been leaking. After three days with fuel and 7+ hours of motoring, no leak.

Ideally, pulling the tank and having it welded would be best, but in a pinch this seems to work as advertised.
The actual application though… for where my leak was located, it took much boat yoga and long arms.