mystery trim problem

[steplift20]

ok i installed a new trim motor, after market cause they dont make mine anymore, the problem is this
I fill up the resivoir and it keeps needing oil after every trip
I see no leak anywhere but i have to keep adding oil
its fulll, go out fishing and have to add some more, every time but see no leak
what do you think i keep it out on a trailer raise it lower it never see any drip marks or anything
what do i look for or what can i do