please help! 250 hpdi problems

[msduckman]

Ok where do I start ? !
I've got a vz250tlrb all updates have been done ! I bought this boat an engine used ! It's on its 6th power head ! I've just made break in on this new one . All filters are new ,plugs new,ecu new 08 model ! The engine is making 5200 rpms an falling flat its not like a dead miss just a stutter . I've tried every thing I've read all my 2 local service techs suggested ! No codes on laptop ! Fuel pressure all good according to tech! Injectors all cleaned and screens replaced ! Last thing done was removed screens bhind plate on high pressure pump! HELP !!! THIS THING IS ABOUT TO MAKE ME NUTTS !

[boats.net]

Thats usually the a loss of high fuel pressure, have to monitor it with lap top while running. Check compression, check that the warning buzzer is working and check for loss of firte to spark plugs when running.

[rodbolt17]

also if fuel pressure stays about 1125 PSI while it falls on its face, then monitor all 6 pulser coil voltages.
if any climb above about 65 volts it tends to shut injectors down.