i had a faulty regulator on my 28 but it was only highlighted when i kept blowing bulbs on high beam.
put a voltmeter on you battery...when running you should be getting about 14v's...my problem was that it occasionally peaked at 19-20 which blew the bulbs. see what yours does at quarter throttle.
however, mine was never serious enough to kill the engine !!?!?? just gave it a quick boost !!!
Dave.