Place chicken in a large stockpot over medium high heat. Cover with water; add 3 teaspoons garlic powder and one teaspoon onion powder.
Bring to a boil.
Reduce heat; cover and cook for about 15 minutes.
Meanwhile. in a saucepan over medium heat, mix together ketchup, one cup brown sugar, mustard, chili powder and remaining garlic and onion powders.
Add remaining brown sugar to taste.
Simmer about 15 minutes; add smoke flavored sauce and cook another few minutes.
Place chicken on an oiled grate over medium-high heat.
Grill for 20 - 40 minutes, turning and basting often with sauce, until chicken juices run clear.
Use a meat thermometer to ensure chicken is cooked to the correct temperature.