I have a 2007 320 sundancer with 2 mercruiser 350 mag mpi engines with v drive. I can idle out of my marina and can go 1000, 1500, 2000 and 2500 rpms with no problems. When I get it up on plane at about 3800 rpms it runs beautifully for 2-3 minutes and then the starboard engine shuts off like I hit a kill switch. No sputtering, just shuts completely off. It happens at the exact same spot every time meaning I'm going the same time and distance. I have talked with mercury techs who have been great but running out of ideas. Hoping for some help. This is what I have done: water pressure and water temp is fine, oil level and pressure is fine and voltage is spot on. Distributor and components look good. Fuel pressure is right on (at idle, I havent had a guage on it when it cuts out) and when I pull the line off the fuel regulator it rises within range like it's supposed to. Gas is good with fresh couple of tanks with fuel treatment always added. Replaced the fuel relay and checked the 50 amp breaker. Fuel module stays cool after running. I tried to inspect all grounds and connections. I switched ignition coils hoping that would be it with no luck. My suspicion is a bad high pressure fuel pump but would it run for awhile and almost for the exact same period of time EVERY time before shutting down? I talked to a fuel pump guy and he said they usually run or they don't, not run for awhile and then stop. Any experience on that comment? when it cuts out it starts again but it seems to take longer and longer every time I go out to start back up and then I can idle back to the dock and run at lower speeds. Throwing up a hail mary here hoping someone has had the same problem or has an idea. Thanks so much for listening.