And are these kit built? If so perhaps the owner know what he was doing engineering wise
Yes, they are kit builds. The fuel tank is behind the seats, and I mean right behind the seats, actually in the cockpit. There is no fuel gauge, you simply look back and see the white plastic tank, you can see the fuel level as a shadow through the clear plastic tank, and there are markings of 10, 20, 30 litres on the side.
If there was any kind of blockage, I'm sure any Jabiru pilot would try and fix it themselves and immediately get airborne again, that's the sort of airmanship these guys display. Whenever you step into a Jabiru aircraft you're basically saying you don't care if you see another day, absolutely terrible aircraft that should never have been allowed to get airborne.