Small Engines (Lawn Mowers, etc.): Lawn Mower Rough Idle, float bowl, orfice

Question
I have a Mastercraft Lawn Mower (I believe the engine is a Tecumseh) it is a 6hsp 3 in 1 mower and is about 10 years old. When I get it started I have to press the primer button a couple of times to keep it from stalling, it the runs for a few seconds and almost stalls again until I press the primer again. After doing this for a few minutes and the engine warms up it will stay running but the engine speed will drop down and almost stall. After about five minutes I can start to mow the lawn but if the grass gets a little bit thick it will stall, after about ten minutes the engine speed might drop down but the lawn mower doesn't stall.
I have changed the spark plug, engine oil and air filter. I have taken the carb off and have fully cleaned the carb.
I have noticed a rod coming from the carb that is attached to a lever on the side of the engine, Is this the automatic choke for the engine, as I have noticed that the lever will move back and forth as the engine idle fluctuates? If I force the lever the idle speed will increase but I can feel the engine trying to push back on the lever.
The engine was running fine when I stored it for the winter and started doing this when I brought it out for the first mowing of this year.

Answer
Something is still blocking a carburetor orfice.  Is the hole(s) in the float bowl nut clean?  Since you have to push the primer bulb I'd say the carb is running lean, not getting enough fuel.

Did you blow compessed air from an air compressor through all the carburetor orfices?

Here is the link to the repair manual:

http://www.cpdonline.com/692509.pdf

The rod you metion it the governor rod.

Let me know about the compressed air and float bowl nut hole(s).
Eric