Welcome to the forum, Dave!
Check for spider or maud dauber nests inside the burner tube:
These nests can be small and tough to get out. You can usually remove the tube, blow with compressed air, and ream it out carefully with a small bottle brush, or a cotton hanky rolled up small so it will fit inside the tube. Shoot some compressed air inside the flue/tube which goes inside the heater body while you're at it.
You may have to adjust the burner tube location slighty to get a pure blue flame.
PS -- Did not watch video . . . keep as much distance from Goo as possible.