I currently am running 4 amps in my boat. All amps are working great but one, the kicker 600.4. It keeps shutting down and my other kicker 800.4 works great and my other 2 class d amps (alpine) are also running fine but the 600.4 keeps shutting down after 20 minutes of play and turns on and off while the rest of system is going strong. I thought maybe the batt's were low but the boat cranks right up and I am thinking maybe it's that they are too hot (not very good air circulation) but why aren't the other amps shutting down. This amp was transferred from my old boat and it worked great. Just wondering if it's time for a new amp?? Any ideas with the issues??