Alternator B Failure Diagnosis

Jeff Noted,

#1  Stator B open circuit output voltage is 3-6 volts 
#2  Stator B leads all show grounded ... to the engine case.
#3  Is there a possible ground failure that might be repaired?


#1.  That's Not Good!
#2.  There's Your Problem.
#3.  By all Means!  It is always a good idea to know what the problem really is before blindly throwing money at it.
       It may just be a pinched wire that needs some minor rerouting and a piece of heat-shrink applied.

Then again you may find the whole thing Fried Extra Crispy!
At least you will know what you have before you go spending the big bucks for no good reason.

Thanks Bill.  I’ll tear into it and see what I find.   A while back there was a mandatory SB to replace the Stators for a series of 912iS engines, but this one was not in that series.   There was also an information bulletin that announced the availability of a new ignition housing with an oil spray nozzle to better cool the Stator. This engine was built before that option was part of serial production so I guess upgrading is something to consider. But, it’s quite expensive. Considering both these bulletins, it might be that Rotax has had some failures of the B Stator.   This engine has 640 hours.