As I don't know exactly how much time is on the engine, I'm using non-synthetic oil for a couple of gallons to break it in. It's Briggs and Stratton Ashless 2-cycle oil mixed at 32:1 with 93 octane gas.
Just found a great site for carb parts. I will likely order my rebuild kit from their. It's
www.learnsmallenginerepair.com . On the home page there's a link to a comprehensive Walbro carb listing for ordering re-build kits.
Hadn't thought about the velocity stack possibility. I may do that one if the other things don't work.
This sure is a great starting and powerful motor. I'm not going to give up on it very soon. I should know more after I fly it again next weekend.