I have a 500 atp, bought it used from a friend, ran it all summer, brought it with me to california. Used it a few times, but now the last couple of times it stopped idling, over heat symbol came on. Thought maybe cause it had sat for a month maybe the thermostat had stuck closed, took it out and no difference. ordered and replaced the water pump and accessaries and replaced no difference. Fan comes on and stays on, to point where it kills the battery. thinking maybe sensor is stuck in hot mode, hence signalling engine is hot and tells fan to run???