Engine sometimes creeps back on trim, fixable?

[JARB]

I have a small problem with my trim/tilt system on my 1997 Yamaha 90hp. If I trim the engine all the way down (in) and then starts to trim up it creeps back down relatively fast. To get rid of it I have to tilt the engine all the way up and back again. After that it works perfectly normal until the next time I trim all the way in..

I cannot find any visible leaks. Do I have air trapped in the system or is it a valve that´s not working properly? I can live with it beacuse I don´t have to trim all the way down to get on plane but if it´s an easy fix and want to repair it.

[LaCajuninNC]

sounds like air to me..bleed the system first..if it still does it then you have a leak somewhere..you might not see it but it could be getting into the motor there is a seal there also..

[Sigma]

Try putting gease on the trim rod tips also could be due to the colder weather and oil thickining?