Roasting a whole chicken with a rotisserie attachment on your gas grill is a good way to cook the chicken evenly, giving it a golden color as it turns. You can prepare a roasted chicken that's as good as those prepared by your local grocery store and send a delightful aroma wafting through the neighborhood.
Set up the rotisserie attachment to your grill. Place a drip pan on the grill with about 1/2 inch of water to add moisture to the roasting process and to prevent flareups from dropping juices. Turn the grill on high, close the lid, and allow the grill to heat as you prepare the chicken.
While the grill heats up, clean the chicken by removing the giblets pack from the cavity of the chicken if necessary. Rinse the chicken completely, inside and outside, and then pat dry with paper towels. Rubbing butter and salt on the inside of the cavity is optional. Truss the chicken to keep the wings and drumsticks from hitting the grill. There are many methods to truss a chicken, the easiest of which is to use one piece of butcher's heatproof twine to tie the ends of the drumsticks snuggly together -- then use a second piece of butcher's twine to wrap under the back side of the chicken to encircle across the breasts, securing the wings to the sides/breasts of the chicken.
The spit (long rod) of the rotisserie will have two sets of prongs to secure the chicken. Make sure the first prong attachment is on the spit, loose at the handle end. Push the spit completely through the chicken the long way (neck to tail opening). Center the chicken on the spit. Slide the second prong onto the spit with the prongs facing the handle end. Now, force the prongs from both ends of the spit into the chicken, and then turn the set screw to hold the prongs in place and, subsequently, hold the chicken in place.
Check the temperature on the grill. It should be at about 325 degrees Fahrenheit. When ready, drop the chicken and spit into place, and turn the burner off directly beneath the chicken. Turn on the rotisserie, and close the lid.
Prepare a basting solution from olive oil or melted butter or margarine, along with desired seasonings such as like salt and pepper. Allow the chicken to cook for 10 to 15 minutes, and then baste. Turn the temperature down to medium. Baste again 20 minutes later.
A 3- to 5-pound chicken will need 75 to 90 minutes to cook; anticipate longer if the lid is opened frequently. It's important to have the lid open as little as possible to retain the heat needed for cooking. To tell when the chicken is done, poke a meat thermometer into the meaty part of the drumstick, avoiding the bone. A temperature of 180 degrees Fahrenheit means the chicken is done.
Remove the chicken from the spit to a platter, and allow it to rest for 10 minutes before carving.
The drip pan, if not included with the grill, needs to be larger than the chicken. A shallow disposable aluminum pan can be used, or you can create a drip collector from aluminum foil with the sides turned up.
Even on gas grills, the rotisserie is operated by an electric motor, so do not use the rotisserie on a rainy day.