Thank you for your question.
I am sorry you are having a problem with the snow blower. By the symptoms you are having I suspect the problem is dirty passages in the carburetor. When the passages start to plug up the engine does not get the needed fuel to run smoothly. Then when you choke the engine, it delivers more fuel and the engine will smooth out. To cure the problem I recommend cleaning the main jet in the carburetor. You will need to purchase a can for carb cleaner from the local auto parts store. Then click on the following link to watch a video on how to clean the carburetor.
How to clean snow blower carburetor
The engine is not the same but it will give you an idea on how to do this. I have provided you with an image showing the break down of the carburetor.
Please use extreme caution when dealing with fuel.
Then after you have cleaned the carburetor, start the engine and slowly turn the choke off.
Please let me know if you have any other question on this problem.
Here is a link to order any parts you need.
Sears Parts Direct
If you do not feel confident repairing this problem yourself, then you can have it repaired at your home by a Sears technician. Here is a link for the website:
Sears Home Services
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