Thread: Under propped?
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Old 03-15-2014, 11:41 AM   #23
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City: Vallejo CA
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Originally Posted by twistedtree View Post
... The Nordhavn has a Deere 6090 M2 rated at 325hp. The M2 rating is full throttle for 16 out of 24 hours, and 100 RPM below that for the balance. So that's 2200 RPM for 16 out of 24hrs, and 2100 RPM for the rest. At 2100 RPM it's continuous rated.
Are we sure we're properly interpreting JD "M" ratings? My JD4045DFM70 is also rated "M2." So, full power operation is allowed 16 hours during a 24-hour period; however the stated load factor is equal to or less than 65% (actual fuel consumption divided by full-power fuel consumption). Sixty-five percent for my engine is about 2100 RPM out of a maximum of 2400 WOT. Thus, in my mind, anything between 2101 and 2400 RPM is "full throttle" limited to 16 out of 24 hours, a 299 RPM spread, not a mere 100 you cite for the Nordhavn's JD. (I usually operate at 1800 RPM, or a load factor of 43%)
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