1991 Yamaha Outboard Factory Service Manual 9.9 and 15 HP, Page 20Get this manual
fBy moving the COl magneto base, bring the ignition mark on the CD magneto base into alignment with the timing mark on the COl magneto rotor aPlace the piston at TDCbTurn the COl magneto rotor counterclockwise and stop it when the dial gauge reads 0.12 0.05 mm (0.005 0.002 in) (5 BTDC)cLoosen the adjusting bolt on the fullretarded side of the throttle cam
1COl magneto base
2Timing mark
dBy moving the COl magneto base, bring the ignition mark on the COl magneto base into alignment with timing mark on the COl magneto rotor