Mike,
I'd be concerned about flying it too! And you may also have more than one issue. You purchased this used and haven't provided much history information. Lets start from the beginning. I recall, you bought this about 8 months ago.
What have you inspected, adjusted, replaced, serviced since you bought it?
Did it have any issues in your pre-purchase flight/inspection?
Did the previous owner have any known issues with it?
Was he/she also the builder?
How many hours total on the aircraft? How many hours prior to your purchase?
Was the engine a new install or used from another aircraft?
Are the log books complete and has all maintenance been performed?
How long did it sit without being run or flown?
I do have a point here, but need to know the history to go into detail.