[THEFERMANATOR]

I will say of all the tachs I've had, my omc tach was off the furthest of any of them. I was propping my built 225, and it said I was turning 5500 or so, dead where I wanted to be, problem was it didnt sound right, then one day it bumped the limiter. I knew the limiter was 6700, so I hooked up my digital tach, and sure enough it was off almost 1200 rpms at wot. So dont assume it being a new factory tach makes it right. Also, theze tachs are driven off the charging system, so any charging issues can effect them as well. If you have the 35 amp charging system, it is common for the magnets to come loose in them, and cause tach issues.