Small Engines (Lawn Mowers, etc.): Carb Adj, arens snowblower, tap tank

Question
   I have a older Arens snowblower with a Tecumseh engine ( HS50  mod 67008A  ser 5279B) After the blower runs for 15 to 30 min it starts slowing down, like it is running out of gas. Next it just stops running and I can't get it to start again. It did this about a week ago. So I loosened the nut at the bottom of the float and drained the gas out. After refilling it would start again. Today I was using it again and the same thing happend. It started running slower and then it just stoped. The blower is at least 30 years old. I have had it about 15 years. Ever since I have owned it I had to run the choke all the way on or it would die. I have noticed that the carb adjsment screw that is located level with the top of the float bowl is only open about 1/4 turn. This doesn't seem right to me but it is the only setting that the engine will run at. There are three adj, screws on the carb. What do you think I should set these at? 1. at the bottom of the float bowl. 2. at the top of the float bowl. 3 one at the top of the carb. Any ideas or help you good give me would be great. 40" of snow so far and more on the way.
             THANKS   JERRY

Answer
Because you need to run it with the choke on, there is a blockage inside the carb.  You will need to remove the float bowl and use a peice of tag wire to push through all of the internal passages.  Then follow up with carb cleaner.  It would be a good idea to clean the entire fuel system as well (filter screen in fuel tap, tank, lines, etc.)  The initial settings for the mixture screws (bottom of float bowl and into carb body above float bowl casting detail) is around 1 1/4 - 1 1/2 turns out from lightly seated.  The third screw (not going into the carb body) is for the idle speed.  Hope this helps.