Just BOB said:
"...Several people have suggested I run them up to 60 to 70% for about 10 minutes of every 4 hours of operation. I have always heard the danger of running a diesel under loaded. Others say it is not necessary to do this and they will run forever at my cruise RPM and load.
What are your opinions?..."
When I first went shopping for the engine for Rainha Jannota, I went to visit the MWM factory and, coincidentally, a major Engineering Manager from International was present. As we were visiting the same person, we both got invited for lunch.
One of the issues brought up to the table, while eating a glamorous Brazilian BBQ, was exactly this so discussed issue of under loading marine engines by running them at very low RPMs. I will reproduce now his final statement about the issue:
Quote”…There two different fields in this discussion. One is the new “Electronic” diesel engines which will suffer if/when running at very low RPMs for long periods of time.”…Now comes the surprise, “…very low RPM on a max 2500 RPM boat engine means less than a 1000 RPM. Yes we have seen some premature charcoal build up in Electronic engines that runs 4000 hrs out of 4500 hrs at idle rpm. The other field refers to conventional non-electronic engines. For these, as far as I know, there aren’t reliable technical/scientific studies/tests that prove the damage on a engine that runs indefinitely at under load regimens, in boats, trucks or even industrial engines…” end of Quote
After listening carefully, I considered this a definitive statement about the issue and bought a mechanic engine.
Regards
Fernando
Note: MWM is a Brazilain company created by Deutz in the 40's, nationalized by the military dictatorship in the 70's, who recentely bought US INTERNATIONAL.