TOHATSU 2.5 Owner's Manual page 17

Note:
(1) Do not use unsuitable or poor-grade gasoline or oil. These may
cause serious damage to the outboard and shorten its life span, as
well as causing starting problems and other troubles.
(2) Always use fresh gasoline. Fuel kept in the fuel tank for a long
period will produce varnish and gum, which can damage the
outboard and create problems in running.
(3) Use only fuel in which the gasoline and oil have been well-mixed.
(4) When Filling the fuel tank, be careful that no dust, water or other
foreign matter enters the tank.
(5) Do not fill the fuel tank up to the top of the mouth ring.
(6) After filling the tank, close the tank cap securely.
(7) When carrying the fuel tank, close the air vent screw and fuel cock
securely, and drain the fuel in the carburetor oil chamber com-
pletely by removing the drain plug with a screwdriver.