This forum is fairly new and doesn't have a huge amount of info to sift thru yet. Can you explain what the problem is and possibly someone here can point you in the right direction. Also consider buying the maintenance manual for your boat.
There are three main areas to consider when troubleshooting - mechanical (condition of the pistons, rings, cylinders, crank, etc), electrical (battery, coils, spark plugs, MPEM, various sensors, starter, stator, votage/regulator/rectifier) and fuel (condition of injectors, quality of gasoline, fuel pump output and fuel filter condition).
You mentioned it is a starting problem. Does it take a long time to start? Is it slow to crank over?