I have a different problem with mine. I have a 14 channel Futaba, of which the reciver pack is 6volts. My skywritter is set up for 9.6 volts. When I hook up the pump to the battery my reciever glitchs like crazy. I called Sullivan and they tell me it is rare but known to happen. There is no cure, but running the pump at the same voltage as the reciever may help. I have not tried that yet, but I did install a power expander and regulator for the reciever which they also recommend with no change. The glitching is major but not always percieveable, depending on radio location from the plane.. about 20 feet or so with antenna fully extended. (it only glitchs with antenna out)

Regards,
Randy