Cut pork roast into 1 inch cubes and place into a large reseable plastic bag. Combine marinade ingredients in a small bowl. Pour mixture over pork, seal bag, and allow to marinate in refrigerator for 2-6 hours. While pork is marinating, place potatoes in a large saucepan. Allow potatoes to cook for 15-18 minutes. Remove from heat, drain, and rinse with cold water. Preheat grill for medium heat.