Nautilus - starts moves fwd a foot/back a foot, then stops!

by jim
(Wilmington NC)

I'm looking at my daughter's Dolphin Nautilus pool cleaner since I arrived at her place - supposedly on vacation!! It has had these symptoms for a while she tells me. It starts - moves fwd a foot- then back a foot, then stops! I've had it apart to make sure nothing is jamming the tracks. I cleaned what is left of the impeller - now ordered a new one. Could it be the impeller causing this problem or is it something else? I've read posts about burnt out circuit boards and resistors.