Honda BF4A Owner's Manual page 46

OPERATION
[BF4A]
OFF
ON
[BF5D and BF6A]
PORTABLE
FUEL TANK
POSITION
INTERNAL
FUEL TANK
POSITION
44
2. If you are using the internal fuel
tank, turn the fuel valve lever to the
ON position (BF4A) or internal
fuel tank position (BF5D and
BF6A) (p. 19).
If you are using the portable fuel
tank, turn the fuel valve lever to the
portable fuel tank position (BF5D
and BF6A) (p. 19).
N (neutral)
GEARSHIFT
LEVER