Twin Yam 200 HPDI on 272 issue

[taylor3351]

2000 - 272 GW with above mentioned HPDI’s. 2 weeks ago everything was fine and boat ran with no issues. Stopped for the afternoon and a local pull up beach spot. Time to leave and head home. Well that’s when the problem arose. While the motors, crank, idle and run without issue they will not come up in the power band. The boat will only come up to 3000 rpm where normally at fill throttle I can get 5000’ish rpm. This is a both motor issue and is not isolated to a single motor.
So the tanks stay full and the boat is dry stored at a marina.
Changed out in-line fuel filters/water separators with no noticeable water or trash noticed in the filters.
Have added fuel treatments and again the boat ran fine for half the weekend last weekend.
Fuel tanks stay full (marina) and I have not had any complaints about bad gas.
Typically I run 50-75 gallons so I’m pretty sure the gas stays fresh.
So recapping. Sudden issue affecting both motors where they will not come up to full rpm but run just fine in idle and up to 3000 rpm with the throttles in the wide open positions
Any thoughts or suggests would be helpful as I’m going to put it in the shop next week unless I can figure something else cause I gotta have my boat. It’s summer time in Orange Beach, Alabama !
Thanks

 

[Newport Grady]

If it affects both then it is a fuel problem (unlikely under your fact pattern) or a control problem. Could the neutral be engaged to some extent?

 

[Fish- on]

Have you replaced the VST filters?

 

[SkunkBoat]

if you had an alarm I would say oil level, oil filter clogged

 

[taylor3351]

Have you replaced the VST filters?

No.. thank you ...
I’m looking those up now

 

[reelserious]

No.. thank you ...
I’m looking those up now

Sounds like VST filters except both motors at once would be highly unlikely. The good news is that the VST filters are routine maintenance on the HPDI's so you have nothing to lose by changing them out and it may resolve your problem. Good luck.

 

[seasick]

Try running with the fuel fill cap off. Both motors starving for fuel has to be related to a single source issue. Since everything else ( with the exception of bad gas) is independent, the only common thing I can think of is a blocked vent. If it runs fine with the fill cap open then the vent is blocked.
Good luck.