John Deere POWERTECH 4045 - Manual (Page 126)

Engine Operation- 4.5 L “270” Engines
OURGP11,000007D –19–27JUL06–1/1
Avoid Excessive Engine Idling
Avoid excessive engine idling. Prolonged idling may cause
the engine coolant temperature to fall below its normal
range. This, in turn, causes crankcase oil dilution, due to
incomplete fuel combustion, and permits formation of
gummy deposits on valves, pistons, and piston rings. It
also promotes rapid accumulation of engine sludge and
unburned fuel in the exhaust system.
Once an engine is warmed to normal operating
temperatures, engine should be idled at slow idle speed.
Slow idle speed for this engine is 850 rpm at factory. If an
engine will be idling for more than 5 minutes, stop and
restart later.
NOTE: Generator set applications where the governor is
locked at a specified speed may not have a slow
idle function. These engines will idle at no load
governed speed (high idle).
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