8.1 horizon engine problem

I have a 2002, 340 sundancer with 8.1 inboards. It starts up fine and runs good to any location. After being on anchor or mooring for 15mins to 2hours, i start her up and she runs fine for about 15 minutes then I get the 2 beeps per minute alarm all the way back to my slip. I called Mercury...

Hello All. I have an issue recently. I have only had the boat for about 5 months. 2006 340 Sundancer with twin Inboard 8.1 horizons. While running at about 24 to 27 mph I lose power in both engines. This happens typically about an hour or two of running regardless of how long I have been on...