I checked the alternator output with a multimeter set on 200 vac, put the red probe on the battery side of the alternator and the black probe to the engine for a ground, and it shows between 27.0 - 30.0 volts and jumps up for a split second to 121 volts and back down to the 30.0 volt mark, and does this repeatly every 5 seconds or so. Whats up with that.?