I have a 16.5 Craftsman lawn tractor (917.271140). After starting it will run in idle only and will run continually without stalling. If the blade or drive gear is engaged, it will stall after about one minute of cutting or just driving. There is no obstruction to the blades. I can keep it running for a short period afterward if I choke it, but it will eventually die. It is then very hesitant to even start.
I have changed the oil, put on a new air filter and replaced the spark plug. I have also sprayed carb cleaner in the carburetor but the problem remains.
What's next?

Hi,
Your manual is located here:
http://www.managemylife.com/mmh/lis_pdf/OWNM/L9120305.pdf
And you should check to see that the engine controls are moving freely(page 55) when you move the throttle lever. Sounds as if you may be having a fuel starvation problem, as well.
Peace,
Clarke