2007-2009 Yamaha F15/F20 Outboard Service Manual, Page 66Get this manual
Control system Engine idle speed: 1,050 50 rmin 3Turn the throttle stop screw in direction or until the specified engine idle speed is obtainedS6AG3180
Timing light: YU-33277-B 3Check that the pointer is aligned with the "T" mark on the flywheel magnet as shown
S6AG3160
NOTE: To increase the engine idle speed, turn the throttle stop screw in direction To decrease the engine idle speed, turn the throttle stop screw in direction b4After adjusting the engine idle speed, rev the engine few times and let it idle to check the stability of the engine