Hitachi NR90GC - 3-1/2" Gas Powered Clipped Head Framing Nailer Technical Data And Service Manual page 21

Problem
Fuel is
The oxygen content of the air
sprayed but
is low in a place such as
no
highlands at an altitude of
combustion
1500 meters or more.
occurs.
<Excessively high
concentration of gas>
Possible cause
Inspection method
A large amount of fuel is
sprayed.
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Remedy
Use the nailer in a place where
the altitude is under 1500
meters.