B&S 31C707-0154-E1 carb ?

I just finished overhauling the engine listed in the subject line. The only thing I haven't done yet is the carb, engine runs good at full throttle, but a little rough at idle. I know the bottom of the throttle shaft is oblong, but I haven't checked the hole in the carb to see if it's out worn out. I believe the carb is a Walbro, but need to pull it off and check the back side of the carb.
My question is should I buy a carb off eBay or rebuild this one?

Thanks,
Bob

B&S 31C707-0154-E1 carb ?