aandere should have some pics of cowl. First thing that hits my mind is overheating. Air in, air out, air over engine and tuning(lean?).

Second is Chinnese CM6 spark plug?

Next is why are you running a 6V battery for ignition? 4.8 for ignition is better! (and lighter)

I'm sorry but with one post only, did you just crawl out from under a rock? ( ha ha )

Have you read the Newbee to gas sticky?

You and "Lucy, have some ssplainen to do".