I'm running a 13,500 btu dometic ac unit on my 2017 coleman travel trailer. I have a westinghouse igen4200 generator 4200 peak watts 3500 running watts. I installed a start capacitor and it will run the ac for about 45 minutes then the generator will overload. I have all the other breakers turned off so its definitley the AC causing the overload. Any Ideas what the problem is?