Hey I have two 2000 yamaha 150 ox66s. One tilt and trim cylinder is leaking out of the top seal. Can I replace the seal or do i have to replace that unit. Thanks

If the shaft’s ok then just a seal kit should work. Release the manual screw to remove the cap.

if the cap is in good shape and not corroded, you can replace just teh seal, however you do have to take it completely apart.
if the cap has corrosion you wont be able to get the new dust seal to seat properly in the cap, then you will need to replace the piston assembly, as that part isnt available seperately.