If your carburetor is flooded, it means that too much fuel has been delivered to the engine and the spark plugs are wet. This can happen if you try to start the engine when it's cold, or if you leave the choke on for too long when starting. If your carb is flooded, you'll notice that the engine is cranking slowly, or not at all. You may also see fuel leaking from the carburetor. To fix a flooded carb, you'll need to remove the spark plugs and dry them off, then try starting the engine again.