Komatsu PC290LC-6K Operation & Maintenance Manual page 101

NOTICE
Cancelling automatic warming-up operation
If it becomes necessary in an emergency to lower the engine
speed to low idling, cancel the automatic warming-up operation as
follows.
1. Turn fuel control dial
for 3 seconds.
2. When fuel control dial
the engine speed will drop.
to the full speed (MAX) position and hold it
is returned to the low idling (MIN) position,
12. OPERATION
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