In a small bowl, combine the ketchup, soy sauce, honey, ground ginger and garlic powder. Pour one cup of the marinade over the chicken drumettes in a gallon-size Ziploc bag. Save the remaining marinade for basting the drumettes during grilling. Turn the bag to coat all of the drumettes and place in the refrigerator for 4 hours overnight. Turn the bag occasionally.
Drain the chicken and discard the marinade remaining in the bag. Spray the grill with non-stick cooking spray before starting the flame or coals. Grill, covered, over medium heat for 15-20 minutes or until the juices run clear. Turn and basting occasionally with the reserved marinade.