Briggs stratton won't start? spark ok, flywheel key ok, fuel ok, backfire as if spark is...

spark ok, flywheel key ok, fuel ok, backfire as if spark is not timed correctly. valves?
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Answers:    You didn't utter if it's overhead valve or not. However it could be a sticky tap, or one out of adjustment. Need more info to make better diagnosis.
Whats going on near my oven's heat thing..??
How aged is you fuel? any chance in attendance may be water within it? Assuming this is ok pull the plug and progress through your start up cycle as if you were starting it beside exception of pushing the primer bulb (do not chock). Sounds like the plug is showery.. Wait ten minutes, replace the plug (wiping it dry first)and try again.