On a rotisserie I'd say about 1 hour - provided the bird isn't over 4 lbs. Now, if you put it on a beer can or something like that and use indirect heat it might take 1 1/2 - 2 hours. But a rotisserie I'd guess at about 1 hour. You don't want to cook this on too low a temp either.
I rub my bird down with a mixture of kosher salt, brown sugar, dried oregano, cayenne pepper, dry mustard, smoked paprika, cumin, garlic powder after I slather on some olive oil or butter.
Be sure, if at all possible, to take some kitchen twine and tie it around the wings and legs to keep them from flopping around.
OK, I stand corrected on the cooking time - everything I've read says 1 1/2 - 2 hours. I know in my table-top rotisserie it takes about 1 hour, but apparently it takes longer using a grill rotisserie.
"Count yourself...you ain't so many" - quote from Buck's Daddy