I have an 88 skeeter with an 88 Yamaha pro v 150. My trim gauge is a Yamaha part. The gauge is out of the boat and the needle is almost 360 degrees from where it should be. It's pegged out almost at the trim low mark. Is there anyway to calibrate it or is it toast?

no way to calibrate it, to do a quick test hook up the pos and neg to a battery and see if it moves. usually if it moves itll work.

There should be a trim sensor on the motor bracket that you can loosen the screws and rotate until its causing the needle to return to down position. It could be the screws are already loose and the sensor rotated on it's own causing the calibration to go out of whack.
https://www.youtube.com/watch?v=WGB_ZPKylRg
https://www.google.com/search?q=yamaha+o...280&bih=678

Missing trilobe pin?

The rolled pin that connects the tilt rod on my Mercury came out causing the rod that holds the motor to the bracket to shift starboard. After having a non-working gauge for many years I am glad that I got a wild hair one day to fix the sender. I had it fixed once under warranty within a year of buying new. When the second sender broke I gave up. I really have no use for a trim gauge any way and forget to even look at it.