I have a 2000 Baja 29' SST Outlaw with twin 454 Mag MPI engines and Bravo outdrives, have had this boat for 2 years. Changed the oil in both engines, boated over to get fuel, noticed starboard engine higher RPM's - discovered spun prop hub.. Replaced both prop hubs and the boat was still not running right - thought that maybe I had got some bad fuel so replaced both Fuel Filters ( there was no water in fuel - I did not prefill the filters with fuel.....). Both Engines in Neutral seem to run smooth and strong however in Gear the Starboard engine will not go over 3000 RPM - checked fuel tank vent to make sure it was not blocked and it appears to be clear. Could this be a Spark Plug Wire/Spark Plug issue?

First time forum user - Thank You

Could be many things. You are probably going to have to give more info to help dial in, but that will just be a better guess.

Off chance you moved some things when doing an oil change? Check to make sure all your plug wires are securely fastened. Years ago, I had a boat shop put on new wires, and they swapped two of the wires. Firing sequence was off. Boat ran fine to about 2800RPM. No other symptom. So there is a case of spark being the issue.

I had a 7.4 do that, screen on the vst pump was all plugged up.

Id hook a scanner to it and see what up, could be a bad sensor causing the ECM to not let the engine rpm

Yup, starty with basics.

Check cap/rotor...these get fubarred (corroded) quickly
VST vent as Phragle mentioned.
Is the engine running hotter than 160*F ?
Fuel pressure check
Computer scanned as F-2 Speedy suggested

And 20+ more things could do it.

So, start checking the basics. Don't use one of these: :wink:

http://www.offshoreonly.com/forums/do-yourself-boating-budget/103342-make-marine-efi-code-tool-less-than-$1-00-a.html

Sure do appreciate the replies, water temp is fine - I will check all of the wires to make sure that I did not knock any of them loose while trying to reach around the engine. If that does not solve it I will run it on a scanner - Will revert back and thanks so much