The basics of how it works are simple and you probably know it already: The flywheel has a magnet on it's inside. As the flywheel spins, the magnet passes close to the stator coil, inducing a voltage across the coil. The level of the voltage varies with the number of windings, the strength of the magnets, and the speed of the engine.
Measuring the voltage out of the coils is not that easy on a non-running bike, since the coil only has output while the magnet is passing through it's field. Chances are that the coil is probably OK if your meter shows a couple of volts on these blips while hand-cranking the engine.
You can disconnect the coil and check its resistance. It should be fairly low, but not a dead short. I don't want to guess at a value for your Moby; I've never measured a Moby coil and don't want to give you bad information.
There's only three things that could go wrong with the coil: it could be physically damaged (broken, water damaged, etc), it could go open (infinite resistance), or it could short (zero ohms).
It's important to keep the coils flywheel and all the wiring and connections clean and free from dirt, grease, rust, etc. As long as you do this, they're pretty much bulletproof.