2007-2009 Yamaha F15/F20 Outboard Service Manual, Page 120Get this manual
Timing belt and sprocket
Removing the timing belt and sprocket
1Remove the flywheel magnet and stator coil assemblyNOTE: See "Replacing the timing belt" (5-3)2Align the "1mark on the driven sprocket with the" mark on the cylinder head
S6AG5H90
CAUTION:
Do not turn the drive sprocket or driven sprocket when the timing belt is not installedOtherwise the pistons and valves will collide with each other and be damaged4Align the mark on the drive sprocket with the mating surface of the crankcase and cylinder block by turning the crankshaft clockwise approximately 90 gradually