Cook sweet potatoes in boiling water 30 minutes or until tender. Let cool to touch; peel and cut into 1/2-inch slices. Arrange slices in a lightly greased 13- x 9- x 2-inch baking dish.
Combine sugar, flour, and salt in a medium saucepan. Add remaining ingredients, stirring well; bring to a boil. Remove from heat, and pour syrup over sweet potatoes. Bake at 325° for 2 hours.