I found a web site with the maintenance manual, mine is on the boat. It lists monitoring the exhaust colour and if it is black is says you are overloading the engine and this should be avoided as it will shorten engine life.
Diesels like to be worked but within limits. It also says if you are running for long periods of time at slower RPMs that every 2 hours you should rev the engine up several times to clear it out.
Web site can be found here
Yeah, I have the same manual and have read that. When it happens, it's pretty obvious it's not good for the engine. I simply didn't understand WHY it was happening. However, as I think about it more, I realize that the opposing forces probably ARE lugging the motor, as if I were going up a hill in too high a gear. Obviously, I can't downshift on a boat, so the only option is to decrease rpm. Although, that analogy doesn't really work, because reducing RPM in the same gear wouldn't work in a truck. I'm so confused
! Just when I thought I knew what I was talking about, I proved myself wrong. Hate when that happens!