MTD fuel pump?

[horses2]

I have an MTD garden tractor w/21 hp briggs & stratton engine. tractor runs good except i have to use almost full choke to keep the engine running. It would run at idle without choke for a short while. I noticed that the fuel filter doesnt fill while running and before I look at the carb, I am wondering if the fuel pump could be failing.
Anyone have some thoughts about the fuel pump?

 

[mostly_gas]

Check for hose splits on the vacuum hose and dust build up on the fuel pump vent. Have had both reduce fuel pump output. Replace 1 pump at 300+ hours

 

[Zork]

there is a vacuum operated pump on the engine. I think washing the pump breather clogs the brass filter more quickly than just blowing the air off. I found pumps online for pretty cheap as compared to the manufactures replacement price.