Walk Behind Lawn Mowers

I have a 7021F walk behind mower purchased in 2009. The discharge plugs when not bagging or mulching much too often. I have had a half dozen of the "cheap" mowers and never had this problem. The discharge seems too small and too restricted to work right. Is there a fix out there like a different chute or cutting the mower deck hole larger? It plugs every 20 or 30 feet and I have to shut it off, tilt the deck, and pull out the plug. Any help is greatly appreciated.

Dale