OK from the pic of your injection pump, your WOT RPM loaded should be 2800 rpm. Unloaded WOT (high idle) is 3130 rpm. Your target loaded WOT should be 2800-2850 rpm. If you can't reach that it will cause overload conditions.
I've got the same pump and engine and can confirm what High Wire writes, not that it needs confirmation.
Except, I wouldn't be concerned if it got to 2600 or 2700 as a high under load, especially if full throttle is measured from the controls.
Lower than 2800 isn't ideal for high throttle operations. But, a lot of people do sacrifice some there to bring high cruise down to about 2000 where the engines run quieter and a lower cruise into the 1500 range, where they are really quiet.
The POs of both of my boat's with Perkins added a HUGE amount of pitch to get more power at low throttle where the engines are quieter. I adjusted ithe props to about 100rpm below the pump spec and the controls to stop another 100rpms before that so I can't slam the pump's throttle lever from the human-facing controls.
Also remember that looking at gauges is only an approximation. They can easily be 5% off. And I've seen plenty 10% off. Your shiny new phototach is definitely the way.
Just don't assume WOT is the controls full forward-- there should be a setback. You can check with the boat off. Fully advance the throttle, then go to the engine room and pop the e-clamp off where the cable is attached to the pump or otherwise disconnect it. Then see if you can advance the throttle lever a but more. Then check again with the throttle lever fully advanced to see if the cable will slide right back on or is too short. Then, when done, adjustbthebthrottlemlevernsonthe cable fits back on and clamp it back or otherwise reattach it.
