cfherrman
Senior Member
I was told that some medium size marine engines can spend a bit of time idling. Read a test paper on one that spent some time producing (from memory) 7 hp per cylinder for over some time over 24 hours maybe it was longer, it showed no ill effects. I think it was a 13,000 hp engine. Evidently for naval operations the engines can spend days at very low power levels. I'm probably the only one but I have never seen a problem with idling for long periods. When a person is running more than one piece of heavy equipment there is always one that gets some long idle time.
Polluting ? Diesel engines use way more air than fuel when idling. What makes them suffer is eliminating the air / oxygen, as in EGR. That is way more worse than idling.
I bet it takes more than 7 HP a cylinder to turn a 13k HP engine so that might be a net hp figure