Second year owning this boat and decided to do my own annual maintenance this year which went great, but I forgot to lift the outdrive after servicing it and when I pulled out of the driveway the bottom scrapped the concrete. Wasn't anything serious as it just barely made a mark on the driveway and did not damage the out-drive except for putting a sharp edge at the bottom of the drive.
The drive trims fine, but the gauge now just goes from "up" to "down" or vice versa depending if I am trimming down or up. The needle does not transgress smoothly as the drive goes up and down. It worked fine before this. Every once in a while it will go to the middle, but never smooth.
Could there have been too much pressure on the drive as I scrapped it coming out of the driveway to damage the gauge. I don't quite now how it works.
Could be a few things. The drive way thing could just be a coincidence and not the reason why the gauge appears to be acting up. I guess it is possible to have damaged the trim sending unit on the drive. It is on the starboard side of the drive yoke. Black plastic disk about the size of a silver dollar held in place by 2 SS 10mm bolts as I recall. Check the wire harness going to the sender as they are known to break with age too. Or your gauge could be just taking a dump. Just check to make sure nothing is broken and then start eliminating things 1 by 1.