CAT3116 both engines not going over 1200 rpm in gear only

[DarDublin]

Hi guys!

Hello everyone, as my first post I will start with the problems haha. So I have princess boat with 2 CAT3116 engines:

STB engine doesn't go over 1200 RPM once in the gear - Revs no problem above that when in neutral.
Port engine is the same , doesn't go over 1200 RPM , except when it reached that RPM the RPM actually drops. - Revs no problem above this mark in neutral.

I have warning light/sound on when I start Port engine. But I don't think it is related , because there is no ECU in this engine I believe. Oil pressure is good and the temperature good - I have gauges to show that. I obviously need to find why the warning sounder does not stop when I start the engine.

Any thoughts? I know there could be plenty of things but where is the best place to start ?

Thank you for any input!

Dar

 

[Portofino]

Clean propellors start there .You haven’t mentioned stern gear hygiene.

 

[oldgit]

First step.
Clean bottom.
Clean sterngear.
This is about 6 months winter growth in a UK. marina.

 

[DarDublin]

New anti-fouling done and propellers cleaned. Boat wasn't used for long time though

PARTIALLY solved the problem - I checked and STB engine turbo was stuck , I sent it off for refurbishment.
BUT Port engine turbo feels ok , that't the engine that is dropping the revs. Could be the injector problem? How to check?

 

[DarDublin]

Also warning sounder problem resolved now - High temperature switch was faulty ..