Thank you for the replies :-)
After more testing.... mine runs as fast as the one in the video when nothing is being sewn - when stitching fabric, it won't go any faster than about half speed. The stitch length in the video looks rather short also, but I'm going to do more research to see if I can find how many stitches per inch it should be (at the longest setting, mine does 18 per inch).
The top tension works well - that's the one thing I can say for sure.
The machine hasn't been serviced professionally, but I've cleaned and oiled (w/ Tri-Flow) everything I could get to by removing a few screws. This was just recently, though - it might need more time to loosen up.
I thought about taking the bobbin assembly apart to clean it. There is a good tutorial here -
http://www.mckennalinn.com/sewing-ma...er-bobbin.html - but that's a lot of steps, pieces and parts. I've dis- and re-assembled the bobbin assembly on a Singer, but this might not make me qualified for the Elna... I'll give the Tri-Flow a couple more weeks and if no improvement, decide whether I'm going to take it in for service or give it a go myself.
Thanks again - I appreciate all of the advice I can get!