149 Carb? High speed running problem
 

This problem seemed to crop up overnight. My 149 won't run at any speed other than idle without some or a lot of choke. The faster the engine speed the more choke is needed to keep it from stalling out. Once the engine is warm it runs just fine at idle with the choke wide open. At high speed the engine sounds fine and runs steady (no hunting) but it needs a lot of choke. The carb is a few months old with probably three hours on it.

I think I ran the gas tank dry a few days ago (I have several Cubs so I don't remember which one or two ran out of gas the past week) so I was thinking maybe some junk in the bottom of the tank got past the inline fuel filter and into the carb and is now blocking something, or the filter is clogged. But before I swap out the carb (I do have another new carb on the shelf) I figured I best ask what might be causing the problem. I just replaced the fuel filter and the problem still exists so I doubt it is a filter problem. The throttle shaft is not hunting at any speed.

The gas is fresh and I used the same gas in two of my other Cubs without a problem.

Clean the carb., replace the fuel line, clean or replace the filter and rinse the tank out, then try it again. You should be good.