I think this is an electrical problem, but I'm not sure where to start. The Motorola tachometer on our boat has a needle (obviously), an hour meter, and a little "clicker" (I don't know what it's called) indicator, which clicks whenever the fuel pump is on, switching between plain white (shown) and white background with a black line. See pic--the red box highlights the clicker thingy:
I'm not sure exactly what that thing is, so any info is appreciated.
Anyway, back to the problem:
I noticed recently that the tachometer needle has started to "dip" by 100-300 rpm every time that clicker "clicks". The actual engine RPM remains steady even though the needle dips. Also, all the other gauges (oil pressure, volt meter, etc.) remain steady.
Is this just some sort of loose connection? Might it be inside the tach? Any suggestions?
As always, I appreciate your help!