Trim Cylinder Leaking Oil

[VANGRADY]

One of my trim cylinders on my '2000 SX250 TXRY (205 hours) is leaking fluid from around the piston rod. My dealer says that Yamaha does not have a seal kit available for this repair. Would anyone know what parts I should order to repair to complete this repair? Also, what would cause the oil to leak? I checked the piston rod and can't feel any scores or scratches on the rod. Should I flush the oil in case there is contamination? How much oil should I buy to re-fill the pumpset?
Many thanks for your advice.

[boats.net]

Seals and orings are available for trim cylinders, not sure which one you have leaking but here is parts list.
2000 SX250TXRY Yamaha Outboard POWER TRIM TILT ASSEMBLY Diagram and Parts

[VANGRADY]

Thanks for your help.