sore,

I'd try running some "Sea Foam" the the carb. You can purchase it at any auto or marine shop. I use it with all my outdoor equipment (1 oz. to a gal. of gas). Go on the heavy side with the mixture to flush out and "snots" in that carb.

Best of luck with you machine, rredogg

I had that problem w/ a recently purchased used chipper engine. Finally figured out the intake valve was sticking. Fed it some marvel oil thru the intake and it smoothed out in two minutes. Runs like a champ now.
Mike

I was thinking "softened diaphram" from the crappy ethanol we have to use but the first two ideas sound good too.