When filling my disco, it takes ages, the main fill line fills up, then gargles down so I can refill it again. Filling the tank took 20 minutes, this is no exageration!!! Ive checked the 1" diameter line that opens out into the filler neck and its clear. I can blow down it with ease into the tank. Ive just been looking in the workshop manuel and it blabbers on about a ROV Roll Over Valve??? Any one had similar problems or know the cure!!!!