Really good question. I have had this more than once, but fortunately not with the current boat. Before the newer storage tank regulations went into effect leaking fuel storage tanks were common here in Michigan. Also, if the marina or wholesale depot did not keep their tanks filled for the winter, they could have significant condensation accumulate. That often showed up as very dirty and/or rusty water in the filter and fuel. I even had water delivered to my home in a tank of heating oil (that is a bad day when the temperature is 5 degrees; you can guess what happened a few hours after delivery). With condensation, it will show up as cleaner water in the bowl of the fuel filter but not get to the engine unless there is a large amount. When I service the engine, I always check the primary filter bowl for water and dump the secondary can filter into a clean container to look for water before disposing of the filter. On a single filter system, I always dump out the filter into a clean container to look for water. I keep 3/4 to 7/8 fuel tank level over the winter in the three boats I winterize and have had no issues with condensation in storage. Another reason for filter changes every season regardless of hours on the meter.
