2007-2009 Yamaha F15/F20 Outboard Service Manual, Page 88Get this manual
Fuel system
2Start the engine and warm it up for 10 minutesNOTE: Because the Prime Start operates when the engine is started, the engine idle speed will be above specificationTherefore, check and adjust the engine idle speed after the engine has been warmed up If the engine idle speed does not decrease after the engine has been warmed up for 10 minutes or more, check the Prime Start system as it may be malfunctioning3Attach the special service tool to spark plug wire #1Digital tachometer: YU-39951-B 4Turn the pilot screw in direction until it is lightly seated, and then turn it in direction the specified number of turns
S6AG4310C