It call having to file the choke plate to where it fits and seals better. I have seen this on larger carbs where they don't close complete as they are hitting side of the carburetor at the air bleeds. Once done it should close better and start better. I currently got a genny is the shop that is mine that I am having to close up the choke plate holes so it can e in 40F weather.
Shouldn't need to do it but sometimes it takes it. Just like I need to re-jet brand new carbs here because the engine manufactures trying to meet US EPA Regs. They are surging because they are too lean until fully warm up after 5 minutes.
