With gravity feed 4 strokes that I only use rarely (in particular my chonda-powered pressure washer, and my spare Honda engine that will fit either of my mowers) I drain the fuel tank by removing the drain plug from the float bowl, with a cup under the drain. I put the fuel back into stock, then reinstall the drain plug before putting the pump or engine into storage. That way I store them with a dry fuel system, and don't waste fuel in the process. That only works with carburetors that have a float bowl drain, of course.
