Cleaning Mark's engine I found what looked like a set screw laying in the engine. After closer examination I found where it belonged. Both are missing from the left carb.

What are there purpose ? Linkage side.

Click to view attachment

I think it's the set screw, that holds the choke tube in each barrel.

It's a cone ended screw and a lock nut thats missing in the photo.
These hold the Venturi in place.

That's what I thought. But wanted to check.
I'll see if I can find something at Ace that might work.

Thanks for the quick response.

The correct bolt should have a beveled point that sits in the venturi tube. . they are suppose to be finger / plus tight had held secure with safety wire

I'll shoot a picture of what I found tomorrow.
The nut didn't seem unique.

Theres usually a nut that goes over the set screw and gets tightened to the carb body, locking the set screw

Gotta love extra parts.