High Altitude Operation - Honda F506 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 fuel mixture will also foul the spark plugs and cause hard starting.
High altitude performance can be improved by specific modifications to
the carburetor. If you always operate the tiller at altitudes higher than
1,500 m (5,000 feet) above sea level, have an authorized Honda tiller
dealer perform this carburetor modification.
Even with carburetor modification, engine horsepower will decrease
about 3.5% for each 300 meters (1,000 foot) increase in altitude. The
effect of altitude on horsepower will be greater than this if no
carburetor modification is made.
CAUTION:
Once a carburetor is jetted for high altitude use, operation at lower
altitudes without rejetting may result in reduced performance,
overheating, and serious engine damage.
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