I found that my 2150 has a port on the rear that comes down from the plate supporting the air cleaner housing that is open to atmosphere inside the cleaner. The line that was connected to that port enters the manifold right beside the manual choke’s hot air tube. Runs much better when I cap it off.

What is this port supposed to be for? Am I missing a component inside the cleaner?

 

It was part of the hot air choke so that the engine was pulling vacuum through the air cleaner.