Preheat grill to medium-high heat. Whisk together ketchup, vinegar, brown sugar, molasses, Worcestershire sauce, mustard, garlic powder, onion powder, pepper and water. Reserve 1/3 cup and set aside. Combine ketchup mixture and chicken in a gallon-size slider bag or large bowl; refrigerate and marinate for at least 1 hour to overnight, turning the bag occasionally. Drain the chicken from the marinade; discard marinade. Make drainage holes in a sheet of non-stick aluminum foill with a grilling fork. Place foil sheet on grill grate with non-stick (dull) side facing up. Immediately place chicken on foil. Add chicken to grill and cook, flipping once and basting with reserved 1/3 cup marinade until cooked through, about 10 to 12 minutes on each side. Serve immediately, garnished with parsley, if desired. Yields four servings.