:welcome: aboard ridcbr to iboats...
Have to tried to jump straight to the starter from the battery? A lot of times people forget about the engine ground connection from the battery. I would remove the ground and clean both ends to bright shiny metal and reconnect to the engine and battery post again. And do the same with the positive wire as well. If still doesn't start, jump from the battery straight to the starter and see it that works. If that doesn't work, you have either a dead battery or a burnt starter that needs replaced. JMHO