I know enough about this to be dangerous! With an 11 year old machine I would assume a diaphragm replacement would be in order. Additionally removing the carb from the tank to clean the fuel screen and fuel pick up tube are probably in order as well.
Anything else to consider as I hope to only do this once!
If it were me and I was going to remove the carb from the engine, I would replace the tank and intake manifold gasket also. Plus as long as I had everything apart, I would give the carb a good cleaning also. This manual might help you out. https://docs.google.com/open?id=0B6NaqjIxWV1ycG8wd0s3Z2Q2X00
Well I got a little ahead of myself, removed the carb, cleaned all I could, replaced the diaghragm, cleaned the tank screen and inlet tube. Gaskets appeared to be in great shape.
It started way easier, but the surging continues. Anything else to consider besides the gaskets??
I don't have an IPL for your engine & can not get one without the code numbers so this might not be applicable to your engine.
If this engine has the long manifold tube that runs across the top of the cylinder remove it and check for cracks.
I replace 3 or 4 of these each season on older mowers because they have split.
