Honda BF8, BF9.9 and BF10 Outboard Motors Shop Manual., Page 305Get this manual
Power Tilt Does Not Hold 1Check the manual valve for tightnessLoose
Tighten the manual valve securely
2Check for oil leakage from the power tilt assembly
Leaking
Repaire the power tilt assembly as necessary (P12-21 thru 43)
Not leaking-
3Check the oil level with the piston rod fully extended (P12-42)
Fill with recommended oil (P12-42)