I have seen internal tank rusting on occasion. It was not that common though. There is a slight chance that someone put some sand or something in the tank. Again rare but kids do strange things sometimes.


I would pull the tank and clean it out to inspect it before deciding anything. I was having a little difficulty with what you have getting through the tank filter to start with. The physical size is too large.


It is almost like the rear rubber fuel line is internally deteriorating. Or the one feeding into the primary filter.