My 1974 Evinrude 135 is "too old" for the local shop to bother with, so I'm on my own. Here's the problem: Trim and tilt work, but leak down quickly from either position. Additionally, will not trim under power. My first thought was that trim and tilt cylinders as well as pump all need new internal o-rings. However, I'm wondering if there might be a simpler matter that's causing this problem. I should add that I do not observe any external leaks. Ideas?