Moller and other compliant ventless portable tank

[kenojim]

Hi, I've not been able to find good information on my problem / question. I have a 6gallon Moller plastic EPA compliant tank. I fully understand the premise of the ventless concept and the vent on the cap only allowing air in..
My issue is when gas is left in the tank and the weather gets warmer I cannot seem to be able to stop the tank from leaking. It leaks around the hex fitting that holds the fuel connection/ pickup. I notice this collar is split?... Not sure all the way in to 2 pieces and if it's supposed to be like this or is the reason it is leaking. ?.
The writing on the tank says the fitting Rotates 360 degrees...
Is that fitting supposed to rotate regardless of whether that hex nut is loose or tight? Or is the hex nut supposed to be tight and have to be loosened to rotate the fuel connector to a different angle, then tightened again?
I appreciate any input on this.. Thanks in advance

 

[JimS123]

My Whaler has 2 of these tanks as oem equipment. One works perfectly, the other leaks as you state.

I have adjusted the hex fitting, looser and tighter and it leaks either way if the temp gets hot.

Sorry, I can't help, but I anxiously await other responses. Obviously, if one works OK, there must be a solvable issue.

 

[airshot]

Ahhhh..remembering the good ole days of steel tanks !!

 

[roscoe]

Hmmmm, I wonder if loosening the cap a little when parking the boat, would prevent pressure build up, and thus keep the tank from leaking?

I wonder. No I don't. I KNOW the answer.

Just like I know if you disconnect the hose from the motor, the pressure in the tank will not force fuel into your motor and flood it.

 

[kenojim]

Leaving the cap loose would just mean the expanding fuel and vapors would leak around the cap instead of where it does now.
(path of least resistance)
The idea of this tank design, like it or hate it is a whole different topic that has been beaten to death. The point of the design to keep the expanding fuel and vapors trapped in the tank, eliminating the venting of fuel vapors to atmosphere and eliminate spills from fuel expansion which it is not doing. And I'm wondering why, is it a defective tank or am I not using it correctly.

And yes if you don't have the Fuel Demand Valve installed I'd think disconnecting gas line from motor (which I do) is a good idea to prevent fuel being forced in to motor.

 

[airshot]

In the old days ( I am 73). I keot my boat in a hoist, under a mooring cover. We still had steel tanks but plastic was just beginning to show up. When I put my cover on I would crack open the cap to release pressure and leave it that way. Sure some minor fumes escaped, but that was good as it kept the spiders away !!! My father had just bought a new motor and yep it hadva plastic tank....after having two tanks split at the seam he also started leaving his cap cracked open, no more split seams and he didnt have any spiders either !!

 

[roscoe]

The idea of this tank design, like it or hate it is a whole different topic that has been beaten to death. The point of the design to keep the expanding fuel and vapors trapped in the tank, eliminating the venting of fuel vapors to atmosphere and eliminate spills from fuel expansion which it is not doing. And I'm wondering why, is it a defective tank or am I not using it correctly.

Really, you tell us it has been beaten to death, then you beat it to death - again.