2000 7.4L MPI hesitation

[JonSnowden]

Hello, I searched this problem but did not come up with anything. I have 2000 Sea Ray with a 7.4 MPI, Its had a hesitation that can mostly be felt under heavy load. Sometimes it will not let the boat get on plane. Without load the engine revs nicely even when you "wack" the throttle. When acting up it looses and regains power intermittently with "light switch" speed/frequency. The boat has all new Plugs, Wires, Distributor, cap, rotor, and coil. I am a very experienced automotive mechanic/technician and I have confirmed all those items where installed properly without fault. The problem appears/feels definitely ignition related and has been ongoing for the last 100hrs. Im leaning to it being a bad Ignition Control Module (ICM) but dont want to just change parts. Just looking for some insight or possibly something who has trouble shot and repaired identical problem. Thank you!!

 

[makomark]

Being experienced with autos, you know about the OBDII port....your engine has a similar connector providing similar data and is usually the best place to start...beyond that, you have the fuel delivery system, from the tank to the rail...in marine engines of that vintage, the ECU doesn't monitor the fuel delivery system.