I don't know what the low pressure side of the pump should be. Don't have the manual at hand. But it is probably the same for all Bosch P7100 pumps, probably in the 10-40psi range. Look that up.
Case pressure is provided by the single plunger lift pump, cam driven on side of the injection pump. Pressure level is determined by a spring loaded relief valve on the top corner of the inj pump. Found this to be a pretty reliable system. Never had to fool with any of this, except leaking primer pumps.
Go ahead and measure the case pressure and compare to your other engine. If they are significantly different, dig into it further.
Measuring case pressure is a bit tricky as there are a lot of pressure pulsations and gauge needle is often a blur.
It absolutely is necessary to know the high idle rpm. I think on the 6CTA 450 it is 2920-3020rpm. But look it up. If that is set wrong, the governor will back off rack position well before the rated 2600rpm. Could absolutely be your issue.
Did this problem suddenly show up? Or has it always been this way in your ownership? Anything done like replacing injection pump? Seen them come back from the inj shop with settings for other ratings.
Also check the simple stuff: Does throttle lever hit the stop at full power?
Edit: regarding your question #2, you don't measure high pressure at the injection pump. It is positive displacement type and if you try to measure that pressure will go as high as the sky until something breaks. The injection pressure is determined by the injector settings, and that can be measured off engine at an injection shop.
Many thanks for helpful tips.
I've owned the boat for the past 10 years. It never had an issue operating to the specs (both engines). I tuned the props to be in 2650-2680 range, so I can keep my engines happy.
Did this problem suddenly show up?
- Yes, this is the first time it happened.
Anything done like replacing injection pump? Seen them come back from the inj shop with settings for other ratings.
- Never had the need to do anything with the injection pump or the injectors.
The issue is on the PORT engine, while STBD side gets to 2600RPMs as expected.
Here´s some additional data and symptoms:
1. The engine seems to work as expected until 2300RPMs. Starts fine, idles fine and no hiccups all the way to 2300-2350RPMs.
2. While getting on plane (out of the "hole") I observed NO SMOKE at all.
3. During my preliminary test runs, I´ve noticed that the engine is also experiencing elevated TEPMs. It didn´t take too long for the temp to rise close to 200*. Once I saw the temp go so high I throttled back.
I´d like to think that high temps and loss of power at WOT are two separate issues. But, I also guess that if there´s a fuel starvation and the engine is working too hard, could lead to elevated temps.
4. While on plane at 2300RPMs, the Oil pressure, on the PORT engine (the trouble side), registered at about 80PSI, which seemed on the high side, as my STBD side was at about 60PSI. This is on analog gauges at the dash. I didn´t verify the numbers on the engine gauges.
5. The boat is always loaded and during my last run had 3/4 of fuel and full water. Environment - hot summer day, air temp in 90s and water temp in
90s.
6. Preliminary observation showed no issues with raw water flow. I´ll investigate it in great detail when I'm back on the boat, but for now no difference between STBD side.
7. Aftercoolers were fully serviced less than 2 years ago.
8. It´s not "the boat". Even though I had some growth on the running gear and my bottom wasn´t in perfect condition during the test. I lost couple knots, but there should be no reason for the PORT side perform any different than the STBD side. It was always the same before.
9. There´s no issue with running gear. I can freely spin the prop with my hands and there´s nothing wrapped on the shaft. Some growth on the running gear was the same as on the STBD side and should not prevent the engine going above 2350RPMs.