Greetings,

Carver 400 CMY, twin Mercruiser 7.4 MPI. 500 hours.

I saw a similar post, but that was for a carbureted boat.

Port engine, has been running well since I purchased the boat Oct 2015. Had both engines fully serviced, including new OEM manifolds and risers. Had an issue with Starboard engine, but looks like it was solved with new MAP sensor.

On a recent cruise, ran for about an hour at 3,200 rpm. Both engines running smoothly, then suddenly the Port engine 'stalls', rpm drops to 1,000rpm, no change to throttle. Bring both engines down to idle, port stalls. I'm able to restart, and fortunately was at the mouth of the harbor (Newport Beach, CA). Motored to slip at 5 kts, both engines seem to be running fine. Did several marina cruises with friends. Engines start and run fine at 5kts.

On way to home port (Huntington Harbor, CA), came up the 3,200 cruise, seemed to be fine. After 5 minutes, port engine begins 'stalling' again. doesn't quite die, but rpm drops to 1,000, again, throttle not changed.

This pattern continues, and I figured out that I could cruise at 2,000 rpm. At 2,500 rpm or above, the engine would start to stall. Made it to home port, no issues motoring to slip.

Come 4th July weekend. I switch Port engine to Aux fuel tank.

Had friends on boat Saturday. Port engine would not start. Sunday morning, port engine fires right up, and was able to do a marina cruise. Monday (July 4th). Port engine reluctant to start, but it does, and was able to do a marina cruise. Like day before, running normally at 5kts, smooth idle.

Following weekend, Port would not start. Had engine guy check it out, showing good fuel pressure, spark at the plugs, no error codes. He could not get the engine to start.

I installed a new fuel filter (primed with fuel), starts right up. Runs normally, and went for sea trial, and ran fine at WOT, cruise for about 20 minutes. Headed back into harbor, and did one last WOT run, and sure enough, stalling starts again. Seems like running out of gas at higher rpm, very smooth down low and at idle.

I think fuel starvation, it feels like it's running out of gas at higher rpm. I think I need to get my engine guy with the Diacom out on the water, and see what's happening when it starts to stall.

Anyone experienced similar problems?

Thanks!