High Altitude Operation - Honda Marine BF75A Owner's Manual

6. OPERATION
High Altitude Operation
At high altitude, the standard carburetor air-fuel mixture
will be too rich. Performance will decrease, and fuel con-
sumption will increase. A very rich mixture will also foul
the spark plugs and cause hard starting.
High altitude performance can be improved by specific
modifications to the carburetors. If you always operate
your outboard at altitudes above
5,000
feet
(
1,500
meters)
have an authorized Honda Marine dealer perform this car-
buretor modification.
Even with carburetor modification, engine horsepower
will decrease about 3.5% for each t ,000 foot (300 meter)
increase in altitude. The effect of altitude on horsepower
will be greater than this if no carburetor modification is
made.
When the carburetors have 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
carburetors 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 carburetors to original factory
specifications
if
modified.
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