I boat in KY and made a trip to Michigan. I must have picked up some different fuel even though I looked the pump over for some indication of blend, additive etc. Boat ran fine for a period of time and then coming off plane at the pier head towards Lake Michigan (four foot rollers in channel) the engine just decided to quit. It would not idle and would die coming off or coming on plane unless I nursed the throttle. Glad it died there instead of the big water.
Stayed in the small water for the day. Upon returning home found my carb all plugged up. Idle circuits stuffed up, two out of four accelerator circuits not squirting, junk in float bowls etc. Idle circuits plugged = no idle, accelerator pump squirter = no come on plane. I have a pre-pump and post pump filter that I changed. Cleaned up the carb real good and all is well now.
My filters were always changed every year and boat is maintained well. My only thought is that the fuel I bought in MI was E-10 or something I have never run before. This fuel dissolved some previous "stuff" and circulated it through my fuel system causing my grief. If the "stuff" it dissolved was a buildup from previous years I suspect it was so small the filter did not catch it or it was in the lines post filters?