Fuel gauge problem
 

My fuel gauge was not working. I was told to ground the hot wire and if the needle moves to full it is the sending unit. Ok replace the sending unit in the tank it works for 2 weeks. I filled the boat up yesterday and when we stopped at Put-in Bay I looked at the gauge and it is not working again! Hard to believe a new sending unit is bad already. Anyone have any ideas on what to look for?? The boat is a 02 PowerQuest.. Thanks.