Place the turkey in a large freezer bag or container with an air-tight lid.
Dissolve sugar, and salt in with water, tequila, and Triple Sec then pour over turkey until it is covered.
Add cayenne pepper, and limes to the bag or container. Shake and marinade for 2-24 hours.
Place turkey on Grill preheated to high, sear the edges, turning every 3 min. After searing, turn off the burner under the turkey and cook with indirect heat from other burners. The roast is finished when internal temperature is 175 Fahrenheit. Remove turkey from grill and allow it to rest for 15 min before serving.