For some reason my tachometer RPM needle is not functioning properly. It tends to jump around, or not work at all. The hours meter works fine. I just installed a new alternator but the problem still exists.
Thank you in advance.
Could be a poor / dirty connection on the tach or the back of the alternator. I’ve had the same problem and solved it by cleaning connections. Worse case is you need a new tach but I think cleaning will fix things for you.
You are smarter than I. Mine was jumping around and then quit. (Mine is driven off a flywheel magnetic sensor.) I cleaned up the contacts and checked the back of the tach. Nothing. I ordered a new tach (new old part). Nothing. I got a new sensor. Found out I have to remove some parts to get a wrench on it. Put everything back together. Now the tach works. Geesh.