2001 Edition Yamaha F225A and LF225A Outboards Service Manual, Page 16Get this manual
GEN INFO Intake system
General information
Throttle valve total of six intake throttle valves are provided, one for each cylinderTogether with the intake silencer that offers enhanced intake efficiency and the injectors that are provided at each throttle body, the throttle valves help to improve the intake efficiency of the engineAs result, this engine produces higher power output and realizes better driveability