Check for vacuum leaks around the carburetor base and intake manifold to cylinder head flanges by using gas from an unlit Propane torch, particularly during warmup. If the engine smooths out or speeds up when you apply the gas to a specific area, you've found your leak. Don't "fowled" spark plugs usually have feathers on them?
Jerry

"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln
Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt!
There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway
Love your enemies and drive 'em nuts!