My trim works good up or down, but on trl or running it, it will leak down slowly, you have to keep trimming it up, no oil is running on ground so it is a internal leak.
Look thru the mounting bracket hole for the manual release valve. Make sure it it shut TIGHT. If so, there is a kit to replace the seals and is relatively straight forward if you follow the steps in the OMC service manual.<br />Good luck
