There should be no gunk on the filter. Clean it out and reinstall it. Then place the spray arms in the dishwasher at the 12 o'clock position. Then start a cycle, let the machine fill and start circulating water for about 20 seconds and then open the door. Do the arms move from the original position?
Running the hot water is a good idea, but these machines heat the water higher than you hot water heater. So if it does not sense that the water temperature is rising it will add time to the cycle to try and heat it .