How do you eliminate the waste spark in a single cylinder engine?
You mean like in a lawn mower type single cylinder engine. You
can try to increase the gap. Increase it just maybe two thousandths
or so at a time. Make sure the plug is good. A faulty plug will not
deliver the desired spark and will cause excess fuel issues also.
If you are having a backfire issue then too muck fuel is probably
present. Usually when this happens the little o-ring is bad in the
carb or the float is stuck open for some reason.