Well this weekend my son and grandson who are rv newbies apparently screwed something up in the rv toilet. The Vent door isn't moving when the flush happens. I looked behind the bowl and it looks like the latch flush (not a petal) is on some kind of pulley system. that is only going so far as to allow water to flush but not to open the door to the tank. Any help suggestions? Tanks................ .. haha.. had to throw some humour in there cause right about now I am alittle upset . hopefully this doesn't require alot to fix.