In a large saucepan over medium heat combine sweet potatoes and water to cover.
Cook until tender; drain and cool.
Preheat oven to 350 degrees.
Peel sweet potatoes.
Into a large mixer bowl place the sweet potatoes; mash.
Add milk, Bourbon, orange juice, brown sugar, margarine, salt and pumpkin pie spice; beat until fluffy.
Spray a baking dish with vegetable cooking spray.
Into the prepared dish spoon the sweet potato mixture.
Sprinkle pecans over the top.
Bake for 40 minutes.