Unless I missed something, I don't see the problem defined.. Does it do absolutely nothing when attempting to start? As in no popping, or anything of the like? Does the engine "pop" properly when choked? After removing the choke, does it "pop" again, but not run?

If it's a matter of "popping" and not running, check your throttle butterfly. When closed, you should see the threaded end of the throttle plate retaining screw... Not the slotted head of the screw.. If you're seeing that, the throttle plate is reversed, and it will not draw fuel properly... This is a problem that I experienced, and was driven nearly nutz....

Just my 2 cents worth... I hope you get it solved. BTW, I've been running 3W engines for years, and love them. But hey, that's me...