Place the split hens in a 13 x 9 x 2 inch baking dish.
Combine the lemon juice and the remaining ingredients; stir well with a wire whisk. Pour the marinade mixture over the hens. Cover and marinate in the refrigerator for at least 8 hours, turning occasionally.
Prepare your grill so that you have medium-hot coals (350 to 400 degrees).
Drain the hens, reserving the marinade. Place the marinade in a small saucepan. Bring to a boil; reduce heat and simmer for 5 minutes.
Grill the hens over medium-hot coals (350 to 400 degrees) for 30 minutes or until done, turning and basting occasionally with the marinade.