Place roast in a large plastic bag. Combine remaining ingredients; pour into bag over roast. Fasten bag securely; refrigerate overnight, turning bag occasionally . Remove roast from marinade; reserve marinade.
Insert spit through center of roast; secure with prongs at each end of spit. Balance roast properly to avoid strain on motor. Insert meat thermometer into thickest part of roast, being careful not to touch fat or spit. Place on rotisserie 3 to 4 inches from low coals.
Grill 2 1/2 to 3 hours or until meat thermometer registers 170°. Brush roast with marinade during last hour of grilling.