Q's:
What did the plugs look like? Sooty? Oily?
What is the idle sitting at when warmed up?
How many miles on the 'Carburetor'?
READ THE FOLLOWING VERY CAREFULLY, AND IF YOU HAVE ANY DOUBTS, DO NOTHING. DON'T GRENADE YOUR MOTOR.
If it has carbon build up, bring up to operating temp, (drive it for about 3-5 miles) remove air cleaner and holding the RPM at 2500-3000, slowly POUR/DRIP a pint of water down the carb, backing off on the water before it dies, and returning to speed, continue till the water is gone.
The water will, upon hitting the hot carbon, dislodge by exploding it. Look up 'water injection' same principle.
Obviously If you pour too much too fast, you can damage the motor. I have done this on gas motors for 40 years, never blew one up.
If symptoms persist, it sound like your carb might need a rebuild.