Two more tanks of my Echo Powerblend and I'm on to my Opti2 my father picked up in Maine for me.
Anyway chef, it's common to have to work out the bugs with these things while they are breaking in, and after.
Seriously though, they are cheap motors bolted to bicycles, the only best thing you can do is use the best motor oil money can buy (after break in) and get better parts (chain in particular, looks nice but sucks beyond belief!) and you will have less issues.
And after awhile your bolts stay put, especially if you use (blue) threadlocker.
And that sringy gunk was motor oil that was too rich or what's left after the gasoline evaporates, some mix gets blown back into the carb onto the air filter because these are reedless motors.