Boat stalls while driving- starts again immediately

I'm driving a 2003 Cobalt and no matter the speed the boat stalls while driving. I'll be going full speed ahead, slow, idle - the boat stalls and then often start back up right away. I don't always have to restart, most often it kicks and restarts on its own. It feels like a hiccup while driving.

I've replaced fuel filter, fuel water separator, coil, added fresh gas, bypassed the kill switch, ran 12 volts directly to the fuel pump, swapped the relays on the computer, checked the alternator output. Nothing has adjusted the stall from happening.

The boat starts fine every time. Never runs hot or overcharges. However, once we start going it stalls, starts back up, and repeat!

Any ideas on what could be the issue? Has anyone experienced something similar? HELP!

 

Walt good morning this is a mercruiser 350 mpi not a volvo penta does your answer change with this info?