RPMs wont increase without restarting

[water1]

2006 Yamaha 200 hpdi with 80 hrs. Throttle will run up the scale to any desired rpm but will not increase rpm once stopped and cruised at stopping point. i.e., if you jump out of the hole to 3800 and cruise, you cannot go to 4000 rpm it begins to choke out, drop back the throttle arm and you get back to 3800 or anything lower. All fuel related filters changed. No alarms have gone off and the mechanic says the computer shows everything just fine. If you drop back to nuetral, you can only get back to the highest RPM of 3800.

If you drop back and turn off the engine, you can run the throttle arm up to any desired RPM. Any suggestions?

 

[rodbolt]

Re: RPMs wont increase without restarting

have you tested the high pressure fuel rail at the problem RPM. was the medium pressure inline filter changed? has the vapor seperator been serviced.
does this mechanic have at a minimum fuel system certs and electrical system certs from yamaha?
the only thing the laptop will say about fuel is if the high pressure is in or out of spec but only at the problem RPM.
the medium pressure must hold 50 PSI at all rpm ranges and the high pressure about 675 PSI at all rpm ranges.
if either cant, the engine runs out of gas and can blow a piston.