Yamaha F25 Owner's Manual page 28

Specifications and requirements
these standards have 65% lower emissions
than One Star-Low-Emission engines.
EMU33861
Four Stars—Super Ultra Low Emission
The four-star label identifies engines that
meet the Air Resources Board's Sterndrive
and Inboard marine engine 2009 exhaust
emission standards. Personal Watercraft
and Outboard marine engines may also
comply with these standards. Engines meet-
ing these standards have 90% lower emis-
sions than One Star-Low-Emission engines.
22
ZMU01704
ZMU05663