Good Morning all...My own experience has been that all of the after market carburetors from back in the day work well if they are set up properly...same with the Zenith carburetors...and that is the key...set up properly...often hard to do...even a new Zenith might need minor tinkering...some definitely do and others are just fine out of the box. Just about the same with people in my humble opinion! Ernie in Arizona