If the carb spray doesn’t work, try this: http://2manytoyz.com/carbfix.html
I was able to use Sea Foam to take care of this issue, as shown in my previous video. However, this time I believe a piece of grit was clogging the idle jet. Not knowing which jet was which, I sprayed each jet one at a time. At minute 6:40, I sprayed the single jet on the right side of the intake. The surging idle suddenly smoothes out. BINGO! Now I know which jet to clean if it happens again. The Gumout carb & choke cleaner was purchased at Walmart. Be careful when blasting a jet, good chance the spray will get you too. A face shield is a good idea!