High Altitude Operation - Honda EM650 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 engine at altitudes higher than 6,000 feet above sea level, have
an authorized Honda generator dealer perform this carburetor modification.
Even with suitable carburetor jetting, engine horsepower will decrease ap-
proximately 3.5%for each 1,000 foot increase in altitude. The effect of altitude
on horsepower will be greater than this if no carburetor modification is made.
-1 If a generator jetted for high altitude is used at a lower
altitude the lean air fuel mixture will reduce performance and may
overheat and seriously damage the engine.
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