Need help with a 912 electrical problem.

[Bryan]

I was flying last night and all of a sudden a heard a loud humming through the headset and as I scanned the gauges the Tach was pegged to the high side. It did this for just a short while and so I did not get to diagnose much. I went up this evening and flew for .3 hrs and it did it again but this time it was even a shorter span. I flew around for a while trying to get it to act up again, but it was getting dark and so I landed. Has anyone ever had this happen?

[jdmcbean]

Bryan,
Check your grounds... IMO grounds are the most common issues.

[Bryan]

Yes this is what it is acting like is a ground. I am getting ready to do some other engine work so will be looking into this a little more. Thanks. So John how are you liking the tailwheel config? How much of a speed gain? Thanks again for the suggestions.