Drain the pineapple chunks, reserving the juice. Add enough water to the juice to measure 1-1/4 cups.

Set aside. Place pineapple chunks, sweet potatoes, and sausage in a 10- x 6- x 2-inch baking dish. Set aside. Combine sugar, cornstarch, and salt in a saucepan. Gradually add pineapple juice mixture, stirring until blended. Cook, stirring constantly,until mixture thickens and comes to a boil; boil 1 minute, stirring constantly. Remove from heat and add butter, stirring to melt. Pour over sausage mixture. Cover and bake at 350 degs. for 35 to 40 minutes.