Well...if you dumped fuel into the carb, and it ran for a second, then i would say it is a fuel issue, not a spark plug issue.
The quality of fuel we get these days, varnishes up fast.
Pull the pump side of the carb apart, and you will most likely find that the screen is plugged. Clean the screen and put it back together and see if that fixes it.
Also in my opinion, that type of spark plug that you used, run hot, and it may not be suitable for your climate. I have seen those plugs cause hot scoring to the cyl and piston damage in the summer time here.... They are designed for cold climates.
Factory certified tech in many different OPE areas.
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