High Altitude Operation - Honda HP250 Owner's Manual

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 power carrier at altitudes higher than 6,000 feet above sea
level, ask your authorized Honda power carrier dealer to perform these
carburetor'modifications.
Even with suitable. carburetor jetting, engine horsepower will decrease
approximately 3.5% for each 1,000 feet increase in altitude. The effect of
altitude on horsepower will be greater than this if no carburetor modifica-
tion is made.
CAUTION: Operation of the power carrier at an altitude lower than the
carburetor is jetted for may result in reduced performance, overheating, and
serious engine damage caused by an excessively lean air-fuel mixture.
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