I have a 2003 Murray push mower model 220011X92A that I bought new back in 2003/2004. Never really had any problems until last week (July 2009). The mower started sputtering and the engine was revving up and down in a regular rhythm. I also noticed that it started using gas like never before. Before the problem started I could mow a large lawn with 1 tank of gas and still have fuel left, after the problem started I can't finish my back yard without refilling the gas tank 2-3 times. It seems obvious that too much fuel is making it into the engine, but I'm not sure where to start to look for the problem.

Hi,
Look far a clogged or soaked air filter first.
Peace,
Clarke

I neglected to mention I did take the air filter off for a short time, and while it was off I opened the throttle all the way for a bit. The engine ran better, but still sputtered and would sometimes die. The air filter wasn't soaked and seemed fine.

Hi,
Not a comon thing but I would say you need to replace the diaphrgm between th carb and tank. I would say it has developed a pinhole that allows the engine to draw fuel through it by vacuum.
Peace,
Clarke

Crigby, that did it. I ordered a diaphragm online, replaced it, and mowed the lawn the same day. Thanks much!