Ok this was on my buddy's 97' OBS. He had a fuel leak coming from his fuel bowl. It had a small crack in it, ok no big deal just swap it out. When we got the old fuel bowl out this is what we found.
The fuel bowl was filled with a gritty sand up to the fuel heater, the pile in the second picture was only about half of it. He said the truck used to be a fleet vehice. Obviously the maintenance was not as good as it should have been.
Change your fuel filter every other oil change and drain the fuel bowl when you do it.