Engine Idling

IMPORTANT: Avoid excessive engine idling. If an engine will be idling for more than 5 minutes, stop and restart later.

Prolonged idling may cause the engine coolant temperature to fall below its normal range. Low coolant temperature can cause 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 it should be idled at slow idle speed. Factory standard for slow idle speed is 850 rpm.