I want to thank everyone for their responses to this question. I decided to go way out side the box and try and run it, just as it sits. It took a little coaxing from the electric starter and one half rich turn on the high speed needle, and it idles and transitions just fine! I know my uncle was good about taking care of his engines but I don’t know what after run oil he used. I put the video on YouTube. I’ll go find the link.

I don’t know how to copy the link. If you go to YouTube, search for “OS 61 first start in over 15 years”