Re: wet plugs
When were the carbs last cleaned?
Often a rough idle plus seemingly fine WOT is a sign the carbs are getting dirty enough to restrict fuel flow in the small passages of the idle circuits.
Some owners religiously add both stabilizer and SeaFoam at EVERY fuel up to keep fuel quality and carbs clean, prolonging the period between carb cleanings by many years.
You MAY try adding SeaFoam to your fuel and see if it clears the idle passages and smoothes the idle as you use this tank of fuel
HOWEVER< that could dislodge chunks of crud and further block a passage and worsen the condition, which would require proper carb cleaning.
Your choice, clean the carbs now, or clean them later, eventually they are going to need done.