I don't know much about the Cobras, but what might help the other guys help you: does it stutter and die like it's overloaded or choking? Or does it slam to a stop?
You can easily get the ESA out of the equation. Just unplug it and see if it still stalls going into reverse. You may have to turn the engine off to get it out of gear though so do this test where you are away from other boats and docks.