Yamaha Outboard F15A F9.9C, FT9.9D F15 Service Manual, Page 210Get this manual
COILS AND TIMING BELT
SERVICE POINTS
Drive sprocket removal 1Remove: Timing belt Drive sprocket Shaft holder 1: NA90890-06069
Loosen the sprocket nut with 36 mm deep socket 2Driven sprocket removal 1Remove: Driven sprocket Flywheel holder: YB-0613990890-06522
A For USA and CANADA Except for USA and CANADA