RE: what causes the engine to backfire or pop??
I BET I FOUND THE PROBLEM!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! He left hid engine with me for the night, I decided to take the carb apart, took the needles out, and when I took the HSN needle out, inside the necks feed hole was a tiny, tiny strip of what looks like fuel line, I'll but a million dollars(if I had it) that was the whole tuning and popipng issue. For these engines thats like pinching a fuel line on a real car and trying to get it to run right!!! I feel soooo much better finally seeing a problem, rather than chacing a ghost!!! I'm gonna flush the carb with some denatured alchohol and put it back together. I bet it'll run like a dream tomorrow!!! Chalk this up as a learning expeirence!! THANK YOU ALL FOR YOUR HELP AND SUPPORT!!!!!!