Europa-List: refueling trouble on the plane

[yannick LAURENS <yck.laurens@wanadoo.fr>]

After a one hour and a half flight, I tried to refuel the plane, but I 
wasn't able to add more than 8 liters. One hour later, I was able to 
refuel 16 liters more.
I don't understand the problem, tank air vent looks OK, has anyone 
experienced this pb ? how is it possible ?
It's quite worrying as the sight gauge is not reliable...
thank's if you have informations

yannick LAURENS
europa classic 
F PSCZ
no 192
based in france
LA BAULE