For more than two years our boat with a new 5.7l 350 mpi has experienced issues not starting under hot conditions. Over countless trips to the shop and thousands of additional dollars spent replacing most electrical parts, wiring, ECM we are still having the same issue. The closest we have been to normal is with one mechanic who discovered that if he unplugged the fuel pump and burned out the fuel when it was in this hot state and just cranking, it would then start when he plugged the fuel pump back in. So our work around was installing a kill switch for the fuel pump that I use to start the engine a couple of times to ensure it's burned the fuel and then toggle the switch back on for the fuel pump and it must be in neutral so I can quickly give the engine a little more throttle and then it will start. Once this engine is started and running she is perfect. Sorry for the long list but I wanted to include the items addressed over the last two years: Vacuum gauge in direct connection w map sensor - vacuum at 15-18 @idle changed map sensor changed cam sensor changed coil and ignition module changed distributor cap and rotor changed fuel injectors and fuel rail changed pressure regulator cleaned and tested injectors changed IAC changed plugs checked plug wires changed ecm changed coolant sensor changed connection on fuel pump harness changed throttle body and tps installed new wire harness changed ignition relay Thanks in advance for any guidance that move us closer to resolving this very challenging fuel related issue.