Last season riding my GTX about an hour without stop saw the 12V low display on. Headed to the dock and when I stopped the engine could hear the starter was still running, had to disconnect the battery. Found the starter solenoid was bad, replaced all seemed fine. Back to the water and trying to get away from the dock with a group started the ski probably 5 times, then 12V low display on and would not start. I have used fully charged batteries and same, 12V low comes on immediately when I hit the start button. Help?