The worst place to store your outboard is in your basement beside your furnace high humidity and warmth will seize an engine in no time. For those that may be storing for extended periods of time or in warm humid conditions, you might want to remove the spark plugs and squirt some additional 2 stroke engine oil or fogger into the cylinders, then roll the engine over by hand to thoroughly coat everything. Re-install the plugs to minimize condensation during the storage period. Today's carburetors utilize many neoprene, rubber, and alcohol resistant materials. Draining the fuel system for storage can put these parts at risk by allowing the materials to dry out and crack.
Most brands have easy to find drain and vent screws.
Pull both screws and inspect the quality of the gear oil while it drains. White or creamy oil indicates you have water contamination. If you find this condition, have a dealer perform a pressure and vacuum test on the gearcase. It should go without saying that if nothing but water comes out of the oil cavity, you're likely in need of something more than seals. In some cases, prolonged use of the same oil can lead to the same oil condition.