Yamaha Outboard F15A F9.9C, FT9.9D F15 Service Manual, Page 362Get this manual
DRIVE SHAFT, FORWARD GEAR, SHIFT ROD AND OIL SEAL HOUSING (FT9.9D) E
Pinion and forward gear inspection 1Inspect: Teeth Dog clutch Weardamage ReplaceDrive shaft inspection 1Inspect: Bearing Weardamage ReplaceShift cam inspection 1Inspect: Shift cam Weardamage ReplaceBearing inspection 1Inspect: Bearing Pittingrumbling ReplaceSleeve inspection 1Inspect: 9Sleeve Weardamage ReplaceLower case inspection 1Clean: Gear case (with soft brush and solvent) 2Inspect: Water passage Mineral depositscorrosion Clean3Inspect: Lower case Cracksdamage Replace