Mine is still having the same issue and with my regular props on that spin to 5000rpms, its happening at 4000-4100rpm and pulls back 200ish rpms.

BTW, I FB messaged with BUP last night and he is pretty sure its my EST module and/or pick up coil going out.

What about the anti-siphon valve?

I did buy a new cap, rotor and ignition module for mine to be safe, gojng to run the boat this weekend.

I hooked up a scanner for codes, nothing. I also ran a fuel pump test with the scanner with a fuel pressure gauge on the rail, 48-49 psi while the pump was cycling, held about 44-45 when it was turned off.

unsure on that, or how you would go about testing/checking that

If your gauge is accurate
Pressure is to high, check/clean the Regulator screen

If it's clean its the Reg

there is a adjustable Hardin pressure reg on mine. Was done with the cam, exhaust, and tuned ecu

OK, I'll retract my statement

no worries, I appreciate your input!

If pressure holds, then anti siphon valve is not an issue

It is likely culprit for bogging/fuel starvation. Seen it a bunch. It is at your tank hose barb that leads to the fuel/water separator on the engine.

Looks like this: