I would do that, but the nearest place to buy one is 75 miles from here, so I figured cleaning it would at least tell me if that was the problem. It did not solve anything. It is making a reasonably good spark, however.
yeah prolly ok but maybe not. One time I did chase my tail cleaned fuel system checked points (yep and old one with points) etc and was still backfiring and carrying on. Changed the plug and fixed it.
do you have something else with the same plug you could swap out?
Try the choke it with the hand or something on the intake while cranking.
It can literally suck debris and crud thru the main jet which is what this sounds like being.
Is it flat head or OHV?
Some of the OHV ones are prone to bend a pushrod.