Hi my name isXXXXX will assist you.
If I could get a model number I can help you better. Check for spark, be sure the stop lanyard is connected. You can get a spark tester at the parts house. Remove the plug wirs insert spark tester, check each cylinder.
If spark is good we need to move on to the fuel system. Since the boat has been sitting the caeburetors are most likely dirty and not letting fuel into the combustion chamber.
After 3 days I'd already fixed the problem which turned out to be a faulty fuel line connection.