how long to cook a rotisserie roast
1 Insert meat thermometer into center of beef roast. 2  Cook on rotisserie over drip pan in closed grill over INDIRECT HEAT for about 1 1/2 hours (rare = internal temperature of 140ÂºF or medium = internal temperature of 160ÂºF).3  Baste beef roast with the reserved marinade while barbecuing. Marinate roast 12-24 hours in refrigerator. 2  Discard used marinade. 3  Preheat grill to medium heat. 4  Insert meat thermometer into center of beef roast. 5  Cook on rotisserie over drip pan in closed grill over INDIRECT HEAT for about 1 1/2 hours (rare = internal temperature of 140ÂºF or medium = internal temperature of 160ÂºF).