Scheduled maintenance cooling tune up on a Gibson air conditioner completed. I visually inspected the furnace. Checked voltage and amps. I inspected the evaporator coil. I checked the temperature difference across the coil. Checked refrigerant charge, voltages and amps. I rinsed the condenser coils with water. Cycled and monitored the system. Operating at this time, but not within spec. Gave customer options.