I greatly appreciate all your help Dan. The machine was tuned just before i got it and runs great with the thinner thread it came with. I threw away the ebay crap i bought and just got a "sunguard" brand (92) from a local store and have had great success with a few tension adjustments.
One more question: when i stitch at a lower speed the top thread goes down the hole and gets hung up in the bobbin area. Is the take up/check spring an adjustment?