Tuning is coming along pretty well on my newly running 20B.  I have run into a bit of a snag.  Until last week I was running only on battery power, then I brought my alternator on line.  When the alternator is turned on, the engine starts to stumble and run rough.  As soon as the alternator is turned off it starts to run smoothly again.  Any suggestions for alternator filtering?

Thanks,
Joe