Call the TM company and ask them. There is no one thing that fixes everybody's problem. Minn-Kota installed a internal ground on my saltwater riptide to fix that problem after I tried all the other above mentioned stuff. The same thing just fixed a friends of mine. Each boat is different. That's where I would start and don't let them tell you that they are not aware of this problem. You can also call Lowrance and see what they say, they are very helpful.