Well that looks like it is doing just fine. One problem with our model Steam and Stirling engines, in my view at least, is that they tend to run too fast, so that a more sedate pace like your video shows, especially with a beam linkage machine, is generally desirable, I think.
One thing I do with mine, that I consider an enhancement, is to use a PM Research Solar One engine burner cap with the single smallish wick, in place of the wide surface area burner provided with the Eco Motor engines. I think the smaller, more concentrated flame, focuses better on the displacers heat cap, wasting less of the fire and fuel, so I seem to get longer and better runs.
Edit: The above technique works with the horizontal model of the ECO Motor engine but does not work with the Rider-Ericsson model as the knock out cap for its open burner is a smaller size than that used for the Solar One!
If you already have one of the older Solar Engines of Phoenix Arizona Solar One engines, or one of the newer models now produced by PM Research, then just borrow that burner cap and give it a try. If you like the result, as I do, then order up a dedicated replacement for your new R-E Eco Stirling and you're good to go!
(Tommy, you have a warped mind ..... I can admire that in a person!!!) ;c)