Orifice Seat in a ZS Carb

["Bollinger, Bob (Bob.Bollinger)"]

I am having trouble passing smog (high CO) on my '79 Spitfire and I
can't lean out the mixture enough to get it below 2% CO (max limit is
like 1.3%).  Someone suggested the needle and/or orifice in the Zenith
Stromberg carb might be worn so I was going to try to replace those.  I
was about to order the parts then the guy at SpitBits said I needed a
special tool for installing and correctly lining up the orifice seat in
the carb.  Has anyone ever done this and do you need a special tool?  I
figured you'd just pry the old one out and tap the new one in.

Thanks,

Bob
79 Spit