Mine was doing the same thing and then i found a vid on Youtube and instruction from another site(google search calibrate Ultrex), the short answer, you have to download the app to your phone update the software and and sync phone with motor and controller and then do the calibration and in the setting you have to change the setting from +2 too -1 or -2 right now the system thinks you have a 20k lb boat and and is over compensating... Ill try and find the link. hope this helps.