D333C not reaching full rpm under load

Hi,

My d333c 66D01651 is in a boat. Ever since I have owned it the maximum rpm I can achieve under load is 1500.

Out of gear I can reach 2000 rpm.

New filters, boat has no growth, new lift pump, injectors cleaned and tested.

Engine sounds perfect at 1500, no smoke.

Checked throttle cable and it seems fine. The boat was once a party boat and would have had many different captains over the last forty years, is it possible that some one made changes to the governor to avoid excessive speed or load?

Anything I can check without special tools.?

Hello Waltini, I would suspect it could have been made to be around 1500 rpm under load to keep everything happy including the water police, I would think the rpm range is good for engine as it works hard but not to destroy it under load, if the pump was touched up I think you would get smoke and more then 1500rpm while working, im sure some input will arrive from some of the club crew that have way more input than I can give regarding the engine output etc

That engine should make 2000 full load RPM continuous with the 8L9650 governor and 8M9140 spring and 20.0 +/- 2 in. Hg. boost

and 0.020" rack setting.

Thanks Busso20, that was my thinking also and 1500 is great but it would be nice to have the option to go to 2000.

Thanks Old Magnet. The engine also has a new turbo.

It has a mechanical stop for low speed and a second one for high speed. Will the high speed stop interfere with top speed under load? I don’t understand how the two work together.

The high speed idle stop should be set at 2180 +/- 30 rpm. The low speed idle stop should be set for 600 +/-10 rpm.

The high speed setting will not interfere with full load rpm unless you have a lower than full load setting.

Thanks Old Magnet always appreciate your input. My next step will probably be to take the cover off and see if I can measure rack travel. And I’d like to check the spring.