In a large bowl, combine the new potatoes, sweet potato, onions, beans, rosemary, and thyme. Stir in 2 tablespoons of the olive oil and salt and pepper. Toss to coat.
Using 2 to 3 layers of foil, create desired number of foil packets. Brush inside surfaces of packets liberally with remaining olive oil. Distribute vegetable mixture evenly among the packets. Seal tightly.
Place packets on the preheated barbecue. Cook 30 minutes, turning once, or until potatoes are tender.