"Bruce in Bangkok" wrote in message
...


Yes there "seems" to be that but mention of "it is bad to run the
engine at low poser" seems confined to the boating world. I've worked
many construction jobs where diesel engines were started in the
morning and shut down at the end of the day. During smoke breaks or
lunch they just sat there and idled. Cranes are a perfect example,
that spend most of their life at very low power settings.

Generator sets - I've never seen a gen set operating manual that said
"run this engine at high power settings".


My guess is that idling during smoke or lunch breaks does not constitute
running at low power for a long time. My understanding is that a diesel
engine is happiest running at a constant RPM under a load that represents
about 80 percent of the engines power rating ... either in HP or watts.

Another issue that enters the picture is if a turbocharger is used or not.

The operator's manual for the Volvo diesels in our larger boat recommends
running at 200 RPM below WOT for maximum engine efficiency.

Our other boat, (single engined 36' GB) has two engine speeds .... 1700 rpm
or Off.

Eisboch