The present invention relates to automatic door assemblies and swing operators therefor. One aspect of the invention provides a swing door operator that has an opening in the housing thereof for easy access to the operator motor. Another aspect of the invention provides a method for servicing a door operator. Another aspect of the invention provides a door operator with a spring force adjusting member that moves in the generally longitudinal direction of the spring structure. Another aspect of the invention provides a method for adjusting the spring force of the spring structure in a door operator. Another aspect of the invention provides a swing door operator with an adjustable stop member.