High Altitude Operation - Honda EB11000 Owner's Manual

HIGH ALTITUDE OPERATION
At high altitude, the standard carburetor air-fuel mixture will be too
rich. Performance will decrease, and fuel consumption will increase.
A very rich mixture will also foul,the spark plug and cause hard
starting.
High altitude performance can be improved by specific modifications
to the carburetor. If you always operate your engine at altitudes
above 6,000 feet (1,800 meters) have your dealer perform this
carburetor modification.
Even with carburetor modification, engine horsepower will decrease
about 3.5% for each 1 ,OOO-foot (300-meter) increase in altitude.
The effect of altitude on horsepower will be greater than this if no
carburetor modification is made.
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When the carburetor has been modified for high altitude operation,
the air-fuel mixture will be too lean for low altitude use. Operation
at altitudes below 6,000 feet (1,800 meters) with a modified
carburetor may cause the engine to overheat and result in serious
engine damage. For use at low altitudes, have your dealer return
the carburetor to original factory specifications.
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