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Flymitch
09-08-2019, 05:17 PM
I have 8-71's.One indie mechanic once warned me of excessive idiling.Is this an old wive's tail or is there something to it?At ORD they leave tugs idiling all night long during the winter.Did a search, didn't see this topic.Thanks!

Photolomy
09-08-2019, 08:59 PM
Depends on what you mean by "idling". Running at the low idle (600 rpm) is supposed to be bad because the engines will be running too cool and the fuel will not fully burn and leave deposits. Running at high idle (900+ rpm) is fine because the temps will be high enough. I would assume that the tugs are at high idle all night. I looked into this myself, and it seems that the truckers had a switch or cable to put the engines at high idle when they leave the engine running. We would simply adjust our throttles I guess. The only time this comes up for me is in no wake zones, but I usually keep it at 900 at least in those zones, but lower it if there is slow traffic ahead. For economy speed, I am at 1200 rpm.

Photolomy
09-08-2019, 09:05 PM
This is an interesting document ...

https://info.ornl.gov/sites/publications/files/Pub61263.pdf

SKYCHENEY
09-08-2019, 09:22 PM
ULSD makes idling less of a problem than it was years ago.

oceanjake
09-09-2019, 12:12 AM
It has to do with unburned fuel “washing the cylinders”, and also vaporized oil coating your coolers. If you don’t pick it up and blow them through, it will turn to sludge and restrict airflow after a while. Depends on your configuration. Naturals don’t have this problem that I know of. TA’s are the worst.