Dropped RPMS

Yes, the 93 - 46' is set up the same way. Is it possible someone ran the racks and set the fuel modulators ( if equipped) incorrectly? They can starve the engines for fuel if they aren't adjusted correctly. It's easy to move the control arm completely out of position to bypass the modulators if you want to remove that possibility from the equation.

The rack is controlled by boost pressure.
I was thinking by-pass blower issue but Skippy J may have a good thought on the turbos.
Still not enough boost, rack controller (modulator) may still not open up all the way AND NO black smoke as usual turbo issues.
Getting into more extreme theory, one engine may be holding down the other.
That supper boost (for lack of anything else to call it) does not come up till the last 4-500 RPM.
All of these can be checked with charged air pressure gauges.
I can't find my air pressure gauge installation pictures. One gauge per turbo and and air-box gauge.
Helped me figure witch turbo failed on us last year.


Skippy J has another good point about blocked fuel tank vents. In storage, bugs or storage tape over the vents needs to be looked at.

The rack is controlled by the governor. The modulator keeps the rack from going to full fuel until boost pressure is adequate to burn the fuel without smoke.I would completely disable the modulators and do a test run. I can't imagine both turbochargers failing at the same time. I also still wonder how clean the underwater gear actually is.

Maybe I should of typed the rack is limited my the modulator instead of the rack controlled by boost pressure.
That may read better.
However it's typed, it's not making HP till there is lots of air pressure in the air box, then fuel flows.

Hummm
My props should be ready at TCP this week. Maybe I can visit?

Nuts
TCP has not completed my repairs yet and you already have some RPM back. So when their done, they will truck them back.
These kids are great and in your hood for real fine propeller work. Tell Don & Paul hi from me.

Next time I'm in your hood, I look forward to exchanging some rum and comradery.

In the mean time, I took some pictures of my charge air pressure gauges.
My air pressure gauges are great and when one turbo started failing, I knew quick witch one.


I do recommend you install some fuel pressure gauges, at least for SOP. Helpful for smarter fuel filter replacement schedules.
Please, please consider installing at least some fuel vacuum and pressure gauges.
They do help a lot.

When it comes time for modulator tuning, you may have the gauges already installed and make smarter adjustments.

Divers
I have witnessed so many bad divers and bad diver stories.
For 20+ years, only one diver we use and recommend in N E Florida.
We moved south a bit and he still services us.

The next sad part is most marinas will not allow DIY bottom diving.
Including just looking at your own bottom.

We also have an air compressor on board and while drift fishing off shore, I'll jump in (hookah) for a check of ducers and zincs.
Clear old crab trap line and back on board in a few. Longer if my back needs some therapy.

I remember an area south of the Stewart inlet in the ditch. Looked like a nice area to drop a hook and check out your bottom on your own.

Keep us up on your performance progress and any other projects in the works.