I have dual Plasma III on N4ZQ.
With engine off(actually, it hasn't been on yet...:-)  ..), the Simpson LCD display shows RPM fluctuating between 11 and 13RPM.
Is this normal/typical? Also, MP reads .20 lower than MVP-50 MP reading. Nothing over which to lose sleep, but...splitting hairs is such good fun.

Angier Ames
N4ZQ