915 Generator Failed New Engine

Would this have anything to do with the oil spray nozzle safety bulletin? I thought that this particular problem affected the generator???

No, I did the official Rotax test last week so that’s not the issue. 

One of a few things could be happening.  

Typically you will only get a FADEC notice of a generator failure if its generator A. The only notification you will get regarding Generator B is low voltage on the airframe bus and a discharge like you are seeing. When the engine starts it runs initially on Generator B, while Generator A is verified. Then once verified, generator A takes over all engine functions and generator B is switched to power the airframe. 

If the Generator A failed the automatic test, then the ECU/Fusebox will not switch the engine functions over to Generator A, which would mean Generator B would remain powering the engine functions and not made available to power the airframe. In this case you would get a generator failure notice from the FADEC regarding generator A, and at the same time see a low and declining voltage condition on the airframe bus since generator B is being commanded to power the engine and remain disconnected from the airframe.  

The best way to know what is going on is to plug in your BUDS software and look at the generator outputs. If you don’t have a BUDS dongle buy one, it’s a must for these injected engines.  Without BUDS you can check the fuses in the Rotax fusebox and test the output of regulators A and B at the fusebox as outlined in the MMH.

Thanks for the reply.  I'll have to run through all of this.  

When my installation was new I noticed that if I turned Start Power OFF before the generator switching had happened (14V showing) I would get a Gen Fault warning. My interpretation was that switching during the time where gen A output is being analyzed disturbed the process. By leaving the switch until I see 14V there has been no issue.