I would definitely change fuel, C12 or equivalent will work. Remove and block off the Power Valve and square up to 92 jets.
That Spark plug looks scary! Turn down the timing a little before you melt something. Try the -8 plugs. Changing the fuel may help too as the X may require more jet than what you have.
Tims suggestion of having another plug to swap will be extremely helpful in checking your tune up.
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Dave Polichena
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