Power Trim

I have an 04 60hp yamaha. This is my 3rd season using it. I alway trim the motor up when I dock it. This year, when I trim it up, it wants to start going down and I found that I now have to use the lock to keep it up. Any suggestions? I don't observe anything leaking.

[boats.net]

It's probably an internal leak, a valve or oring leaking and not holding pressure.

[cyrillefrenchy]

hello
try this: remove the trim unit, drain and try to flush the reservoir with clean oil ,make the trim unit to go up and down with clean oil inside, re install and refill to level and try.
the oil get contaminated quickly,making the check valves not to close properly, sometime clean oil help, i already " saved" 2 trim units doing that.
the best is to remove the electric motor and to clean and drain-flush the inside where the oil pump is located, you will see plenty of "saw dust"on the bottom. the kind of "steel paste" you find on the magnets on some engine oil drain plugs.
cyrillefrenchy