Carburetor Modification For High Altitude Operation - Honda Marine BF8A Owner's Manual

TECHNICAL AND CONSUMER INFORMATION

Carburetor Modification for 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 outboard motor at altitudes above
5,000 feet (1,500 meters), have an authorized Honda marine dealer perform
this carburetor modification.
Even with carburetor modification, engine horsepower will decrease about
3.5 % for each 1,000-foot (300-meter) increase in altitude. The effect of
altitude on horsepower will be greater than this if no carburetor modification
is made.
NOTICE
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 5,000 feet (1,500 meters) with modified carburetor may
cause the engine to overheat and result in serious engine damage. For
use at low altitudes, have an authorized Honda Marine dealer return the
carburetor to original factory specifications.
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