Boil zucchini until tender. Drain and let stand in cold water for about 5 minutes, then drain.
Put the zucchini, evaporated milk, sugar, egg, margarine, flour, vanilla and salt into a blender and blend until smooth.
Pour into unbaked pie shell. Sprinkle with cinnamon and nutmeg. Bake at 425 degrees F (220 degrees C) for 5 minutes. Reduce heat to 325 degrees F (165 degrees C) and bake until set.