Had my boat for almost 2 years now. It runs well but has had an issue on the water since I got it. I can drive around at WOT no problem, troll around anywhere above 1200 RPM. If i set it anywhere below 1200 it will die, sometimes in a few minutes, sometimes immediately. This becomes an issue approaching the dock slowly without the motor dying. Changing the plug didn't help, use some evinrude engine tune up and it didn't help. Anything I should be looking at that I can do at home?