Carburetor Modification For High Altitude Operation - Honda Harmony H2013HDA Owner's Manual

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Carburetor Modification for Higln 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 a specific modification
to the carburetor. If you always operate your lawn tractor at altitudes
above 6,000 feet (1,800 meters) have an authorized Honda lawn
tractor 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 an authorized Honda lawn
tractor dealer return the carburetor to original factory specification.
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