What holds the outrive in position while under way? Is there a check ball or some form of one-way valve in the trim cylinders that prevents the drive from moving under acceleration? I suspect that my cylinders or trim pump may be 'weak', allowing the outdrive to move causing constant re-trimming. I noticed the problem just before I took the boat out of service to pull the motor for rebuild. I have looked over my manual (#2), and can't really seem to pin it down. It's a '77 Merc. 888.
