Fuel Tank leakage

[Capt Paul]

Hello all,

Well, a couple of years back I posted about my fuel tank having a leak around the inspection port and sender area. We put new gaskets in and made sure we had a snug fit. Well, I found a small amount of diesel fuel in the bilge again last weekend and sure enough after popping the back deck we found the same spots leaking again.

Has any one had the same issues?? Maybe I'm running the boat too hard when the bay is choppy and causing to much pressure on the seals ??

I am having the vent lines shortened some and re-positioned to help with the slower then desired fueling speed as well. My mechanic said they definitely had a sag in them that was collecting fuel and not letting the tank vent properly. Wondering if this has anything to do with it as well....

Paul

[DougSea]

Has any one had the same issues?? Maybe I'm running the boat too hard when the bay is choppy and causing to much pressure on the seals ??

Seems unlikely to me. That should just be sloshing the fuel around, not putting "real" pressure on it. Is there any kind of crease in the tank or is it flexing? Hoses (connected to the fitting) that aren't secured and are moving around?

And that fill speed can be a pain can't it? Had the same problem on our 28, and an MUCH worse one on an Aquasport we had years ago where the vent line actually looped below the tank!
Before fueling on the 28 I used to walk side to side slowly, sitting for a moment on each gunnel, to help make sure any fuel that had found it's way into the vent lines had drained back down. Seemed to help.

[RobS]

Tough to say why it's leaking without getting a good look at it but half the battle is won with the fact that you have identified the leak and have access to it. If it is leaking beacause you are running the boat hard it is only because it's not a good seal to begin with. Try some Rector Seal on a new gasket. I use it on all threaded fittings and hoses.

[Capt Paul]

Doug and Rob,

Thanks for the reply, looks like it is just a bad seal overall, we are looking at ways to make it better. After just replacing it with newer rubber seal ect. we pushed down on the top of the tank to build up some pressure (the vent hoses were squeezed so air could not escape) and heard air coming out the seals. So we are thinking about it some more. I let you guys know the final outcome here.

Paul

[Capt Ron]

I have the same problem and I know why mine leaks. When replacing the fuel sender a few years ago I found the threaded screw holes in the tank were open to the fuel, not blind holes as they should be. The gasket for the sender will do a fine job of sealing the sender itself but there needs to be small gaskets under the screw heads to prevent the fuel from migrating up the threads and out between the screw head and the top of the sender. I didn't have time to correct this while replacing the sender so now I don't fill the tank unless I'm going to use the fuel quickly.

[RobS]

I have the same problem and I know why mine leaks. When replacing the fuel sender a few years ago I found the threaded screw holes in the tank were open to the fuel, not blind holes as they should be. The gasket for the sender will do a fine job of sealing the sender itself but there needs to be small gaskets under the screw heads to prevent the fuel from migrating up the threads and out between the screw head and the top of the sender. I didn't have time to correct this while replacing the sender so now I don't fill the tank unless I'm going to use the fuel quickly.

Rector Seal No5 would certainly take care of this issue.
http://www.rectorseal.com/RectorSeal-No-5.php

[mudskipper]

Keep in mind that senders work by variation of the negative ground. sometimes there is a staple in the gasket and if you gloom it up too much it might not send. Tank probably has grounding lug too.

[RobS]

Keep in mind that senders work by variation of the negative ground. sometimes there is a staple in the gasket and if you gloom it up too much it might not send. Tank probably has grounding lug too.

The sender has a dedicated NEG. There is no contact between the sender body and the tank. The Centroid capacitance sender has a plastic body.

The tank is bonded.