Hi PeterParker, On our 2520 PH/300 Yamaha, there's a small black plastic mechanical 'lever'/sensor that sends the signal to the gauges to show the trim/tilt angle; it's accessible even from the Armstrong bracket, and is near/above/right of the trim/tilt mechanisms (on the upper-right starboard side). It's easy to access when you raise the engine up. This 'lever' gets stuck on occasion. Just move it up and down manually, clean it off, then squirt some 303 Protectant on it to clean and lubricate it. This process has 'fixed' ours numerous times.... If it doesn't work for yours, it may be a bad sensor or other issue....
They still aren't matching.mine do the same, I have to use the individual trim buttons on the controller to even them outNot to Hijack; but, may be useful. How the He11 do you get the twin motors to indicate the same height (when they are the same height). I am suffering from OCD. My port motor trims indicates at a different rate than the starboard. Going up the port lags behind the starboard. As I continue up the port engine passes the starboard engine and starts flashing orange on the 6YC. Today I bought two new cam clamps and put them on the engines after bending the port one up and down, trying to match them, until I broke the tab off.
