"My Brother-in-Law Has a 2001 cruiser with twin 7.4 MPI Horizons. The starboard engine is alway hard starting. When it does start it runs like it's running rich. The black smoke confirms this. We replaced the fuel pump, fuel cooler, regulator and the Fuel/Water separator even reset the computer. The engine runs perfect beyond idle. I'm thinking it's the idle circuit and/or its components. Maybe a partially plugged air oriface. Anyone care to comment or have any ideas?