"Any suggestions?"

Yes, post the make and model numbers of the ENGINE.

Walt Conner

Well, if the tank still had some debris- it could have made it back into the carb. A deteriorating fuel line will also contaminate the carb. You would have to pull the bowl and have a look. Other possibilities maybe a poor seal on either end of the intake manifold. A squirt of carb spray in those areas while it is running may help confirm this. Could maybe be the flywheel key is sheared a touch. Or maybe it just likes to sputter like a good Tecumseh should...