Honda EB5000X Owner's Manual page 23

3. Turn the fuel valve to the OFF position.
FUEL VALVE
High altitude operation
At high altitude, the standard carburetor air-fuel mixture will be excessively
rich. Performance will decrease, and fuel consumption will increase.
High altitude performance can be improved by installing a smaller diameter
main fuel jet in the carburetor and readjusting the pilot screw. If you always
operate the generator at altitudes higher than 6,000 feet above sea level,
have your authorized Honda Generator dealer perform these carburetor
modifications.
Even with suitable carburetor jetting, engine horsepower will decrease ap-
proximately 3.5% for each
1,000
foot increase in altitude. The affect of
altitude on horsepower will be greater than this if no carburetor modifica-
tion is made.
CAUTION: Operation of the generator at an altitude lower than the
car-
buretor is jetted for may result in reduced performance, overheating, and
serious engine damage caused by an excessively lean aidfuel mixture.