Thaw the turkey, if frozen. To properly thaw a frozen turkey in the refrigerator allow approximately 24 hours for every 4 pounds. Fill the deep fryer halfway with oil and heat to 375°F. Remove giblets and neck. If present, remove and discard plastic leg holder and pop-up timer. Rinse the turkey thoroughly with warm water, or completely cover with warm water and soak for no more than 30 minutes to ensure the cavity is free of ice.
Set out a small bowl for the dry rub. In the bowl, combine all the dry seasonings and mix well.
Set out a measuring pitcher for the injecting marinade. In the pitcher combine the oil, water, lemon juice, mustard, salt, poultry seasoning, and garlic powder. Whisk well to immulsify the mixture.
Pat the turkey completely dry on the outside and inside of the cavity with paper towels. Using a marinade injection syringe, inject 1/2 cup of the marinade in each breast. Inject 1/4 cup marinade into each leg and thigh.
Sprinkle the turkey generously with turkey dry rub seasoning, completely coating the outside of the turkey and inside of the cavity.
Place the turkey, breast side up, in the fryer basket. Slowly lower the basket into hot oil, being careful not to splatter hot oil. Fry turkey for 3 to 4 minutes per pound. Lift the basket from the hot oil slowly. Insert a meat thermometer in the meaty part of the breast; turkey is done when it reads 165°F. If the turkey is not done, lower it carefully back into the oil for an additional 5 minutes. Once the turkey reaches the desired temperature (minimum 165°F), remove from oil.
Allow the turkey to rest and drain in the fryer basket for 10 minutes before removing for carving. The turkey can remain in the basket to cool until ready to serve.