Had my 1998 302 out for the first time and everything seems good except at times the separate trim gauge that is part of the Kplanes gauge doesn't seem to work all that well. One side wants to only work sparatic. Is there an adjustment or something that may need cleaning on this? Is this what the extra "arm" that is attached to the one side of the trim cyl is for?
On another note.....twin 454 mags running 4800 runs 70 on GPS turning stock baja 25 props.

Yes and the arm can stick. See if you can move it freely on the trailer.

That's you drive trim indicator.

My bet is the cable is sticking....my 29 O/L did the same thing

it is the drive trim indicator gauge that is sticking on the starboard side. Can the cable be lubed somehow?

X2.....my port drive is starting to do it now....time to change the cable.

I tried to clamp in a piece of rubber hose to the end of the
cable, filled it with penetrating oil, blew compress air into it and it didnt work... mine would quit working once it got past 6 ..I never trimmed farther than that, so I quit screwing with it.

To fix it right, you'll need to replace the cable.