Office of Steam Forum for Model & Toy Steam Gas & Hot Air Engines

Thanks to Jim (OP) and those who answered this thread I finally got the PM #13 to run, but only in short 10 second burst. I think this was the first time this PM Solar Engine #13 was even ran, and it looks like the original owner must have given up after they built it. The PM #13 is a basic pre-machined kit model (vaguely similar to the Op’s #7) that the “thinking man” assembles. https://www.pmmodelengines.com/shop/solar/solar-engines/solar-engine-13/
This is the only solar/stirlling engine I have, but I can see a lot of little areas where a novice could simply make an assembly mistake. I thus wonder why PM doesn't have better YouTube videos for their products, especially with the massive influx of cheaper Chinese engines flooding the marketplace.
So, anyone have advice on how to tweak any longer run times from these PM Solars ?
[apologies if I am mis-stepping into the original intent of this thread]