not pulling full revs

[kiwi steve]

Hi to All from sunny N Z.
I'm hoping someone may be able to shed some light on a problem I have with one of my DD 8V92 twin turbo motors. I am unable to pull full revs.I can only get to 1800 rpm. Used to be able to get max 2300
I had the bottom cleaned, anti fouled and prop speed done in Feb this year. At the same time I had the shaft's checked for alignment, and the props balanced and the pitch checked. All was well until a week or so ago. I have had a diver go over the side to check that there is no damage or fouling of the props.
All's was as good as when the work was done. I have put new fuel filters on, But still cant get passed that 1800 rpm range. No blue, black or steamy stuff coming out the rear.
Any ideas would be greatly appreciated.
Thanks in advance.
Kiwi Steve

[SKYCHENEY]

Will they make full RPM with No load (in neutral)?

[oceanjake]

You have no smoke. That’s great! I would check the mechanical linkage for slop. Perhaps try disconnecting it and manually moving it to full fuel while someone else mans the helm. If you do not find your missing rpm’s there, you could have a worn or misaligned governor. I once lost several hundred rpm’s and they were found again by twisting the governor and retightening a couple of bolts.Have you used a phototach to verify you are down to 1800 at wot?

[kiwi steve]

Yes it will rev out to max whilst in nuteral. I will check the governer and report back. I have to say that these motors have been absalultely briliant, apart from the fact that they like a drink, then again so does the skipper.

[Boatsb]

Rev out to what under no load. They should be higher than the 2300 loaded at wot without a load.

[pdog]

I had a similar problem a couple years ago. Turned out I had one bad injector on port motor which would not allow it to build more than about 1800 rpms.

[kiwi steve]

Thanks for that info Jason. That congers with what my DD engineer is saying, so will go down this track and hope for the best.