Just an update – I checked the fuel pump for leaks and it checked out good.
I then took out the low speed needle and noticed some red fibrous looking stuff on the end of the needle. I first thought it might be old packing that I missed while cleaning.
Then on closer inspection I realized it was threads from my cheap red Harbor Freight shop towel that I had probably stuffed it into the hole to wipe the threads clean and snagged on a burr. I removed the carb and disassembled for a thorough inspection. Reassembled and back into the test barrel. Ran good and idled down fine once I found the sweet spot on the needle. Lesson learned.
This one likes the needle somewhere between 1/2 to 3/4 turn out from seated and is very sensitive. I’m gonna keep it a couple more days to run it and make sure it’s happy before delivering it to the owner again.