Old 08-24-2020, 04:27 AM
  #5  
hipmotized
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Default cummins

I have 420hp QSB6.7's, have the same issue on the top of port engine (not on starboard) my mechanic says prob from moisture sitting on engine and then getting baked on as engine heats (paint discolors) (this engine is more exposed to the opening in engine room door/gutter when washing boat) He says not a serious issue- just cosmetic.I run these engines mostly at 75% load, sometimes at 80% load and occasionally 85% load.(at end of trip a short run at full load)..so not overloaded by any means

engines have never overheated, they run at 169 degrees at 65-80% load and at 85% load 171 degrees.

let me know if a diesel expert tells you something different.