There are two motors in the RC Series Rainbird indoor and outdoor Controllers. There is a timing motor that allows the controller to keep time and is responsible for slowly moving the large dial slowly through the watering stations when the sprinklers are in a watering cycle. This timing motor can easily be differentiated from the other motor, which is the Advance Motor, because the Timing Motor has a much shorter shaft.
Two easily noticed symptoms of a defective Timing Motor is that your controller no longer keeps track of time. If you set it on the correct time and check back in an hour, it is still sitting on the same time you set it on, hasn't moved. The other symptom would be that if you advanced the large dial to the first watering station and left for a shopping trip, watering station one would still be watering when you got back three hours later.
Keep in mind that the plastic gears inside the controller frequently develop cracks near the hubs of those gears on older controllers, so you may not cure the problem by installing a new motor. We recommend checking for cracks before purchasing a motor.
Motors are easily installed , as they are mounted with only two easily accessible screws and are connected with two wires that cannot be mixed up. If you have no cracks in your gears and your controller doesn't keep track of time or move the large dial forward through your watering stations, chances are a new timing motor may cure the problem.