We have a Lowrance Ghost trolling motor that keeps shutting off after 15 minutes of running and don't know why. Searching for answers. We have taken the trolling motor to the marine shop and they can't find anything. It has new batteries, new wiring going into the boat, and all has been checked by the marine mechanic. They can't find the answer for why it keeps shutting off. Lowrance said that they don't know what the issue is. Any suggestions from anyone?? Please help!! Pat