Big Block Chevy, MSD Ignition, Coil, Holley Double Pumper. Boat running down river starts to cut out, eventially dies. Boat would fire but immediatly dies. Mechanical Fuel pump is providing sufficient fuel as per fuel pressure gauge. I replaced the coil. I thought maybe alternator but after charging battery to full charge, it still fires and then immediatly dies. Will MSD box run on full charged battery or could my alternator be bad. Any help, thoughts on what to check would be appreciated.